Token-based electrosurgical instrument activation

ABSTRACT

An electrosurgical connection unit for a surgical robot arm to connect an electrosurgical instrument attached to the arm to an electrosurgical generator. The electrosurgical connection unit includes an input port connectable to the electrosurgical generator, the input port configured to receive a driving electrosurgical signal and output one or more activation signals; an output port connectable to the electrosurgical instrument, the output port configured to output the driving electrosurgical signal received on the input port; one or more activation switch units, wherein activation of an activation switch unit causes an activation signal to be output from the input port indicating a driving electrosurgical signal with a desired waveform is to be activated; and a control unit configured to selectively activate one of the one or more activation switch units in response to a control signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of U.S. application Ser. No.16/289,854 filed on Mar. 1, 2019, which claims priority to UKapplication No. GB 1803379.5 filed on Mar. 1, 2018, the contents ofwhich are hereby incorporated by reference in their entireties.

BACKGROUND

It is known to use robots for assisting and performing surgery. FIG. 1illustrates a typical surgical robot 100 which comprises a base 108, anarm 102, and an instrument 105. The base supports the robot, and isitself attached rigidly to, for example, the operating theatre floor,the operating theatre ceiling or a trolley. The arm extends between thebase and the instrument. The arm is articulated by means of multipleflexible joints 103 along its length, which are used to locate thesurgical instrument in a desired location relative to the patient. Thesurgical instrument is attached to the distal end 104 of the robot arm.The surgical instrument penetrates the body of the patient 101 at a port107 so as to access the surgical site. At its distal end, the instrumentcomprises an end effector 106 for engaging in a medical procedure.

A variety of surgical instruments are known, each adapted to perform aparticular surgical function. FIG. 2 illustrates an example surgicalinstrument 200. The surgical instrument comprises a base 201 by means ofwhich the surgical instrument connects to the robot arm. A shaft 202extends between the base 201 and an articulation 203. The articulation203 terminates in an end effector 204. The articulation 203 permits theend effector 204 to move relative to the shaft 202. It is desirable forat least two degrees of freedom to be provided to the motion of the endeffector 204 by means of the articulation.

An electrosurgical instrument is a surgical instrument adapted toperform electrosurgery. As is known to those of skill in the art,electrosurgery is the passing of a high frequency (i.e. radio frequency)current through tissue to cause a desired effect (e.g. cutting thetissue or coagulating the tissue). Although the term electrosurgery isoften used interchangeably with the term electrocautery, electrosurgeryand electrocautery are separate and distinct procedures. Whereelectrocautery uses heat conduction from a probe heated by a directcurrent (DC), electrosurgery uses radio frequency (RF) alternatingcurrent (AC) to heat the tissue by RF induced intracellular oscillationof ionized molecules that result in an intracellular temperature.Accordingly, during electrosurgery the patient is included in thecircuit and current enters the patient's body, whereas duringelectrocautery current does enter the patient's body.

There are two types of electrosurgery—monopolar and bipolar. Inmonopolar electrosurgery the high frequency current passes through thepatient from a live or active electrode of the electrosurgicalinstrument to a separate return electrode placed on the patient, whichmay also be referred to as a dispersive electrode pad, a grounding pad,a neutral electrode, a grounding mat, an indifferent electrode or apatient electrode. In bipolar electrosurgery the active and returnelectrodes are both within the electrosurgical instrument and thecurrent passes through the patient from the active electrode of theelectrosurgical instrument to the return electrode of theelectrosurgical instrument. An electrosurgical instrument which isconfigured for monopolar electrosurgery (e.g. an electrosurgicalinstrument that comprises an active electrode only) will be referred toherein as a monopolar electrosurgical instrument, and an electrosurgicalinstrument which is configured for bipolar electrosurgery (e.g. anelectrosurgical instrument that comprises both an active electrode and areturn electrode) will be referred to herein as a bipolarelectrosurgical instrument.

Electrosurgical instruments receive the high frequency current (which isreferred to herein as a driving electrosurgical signal) from anelectrosurgical generator, which may also be referred to as anelectrosurgery generator, electrosurgical end unit, electrosurgery endunit, or ESU. Electrosurgical generators are generally capable ofgenerating multiple different current waveforms to achieve differentsurgical effects. For example, many standard electrosurgical generatorscan be configured to generate COAG, CUT and BLEND waveforms. The COAGwaveform consists of bursts of radio frequency, which when used at a lowpower setting causes a desiccation effect, and when used at a high-powersetting causes a fulguration effect. The CUT waveform is a continuouswaveform at lower voltage, but higher current than COAG, which causesthe tissue to be cut. A BLEND waveform is essentially a CUT waveformwith a lower duty cycle than a CUT waveform. A BLEND waveform typicallyhas a duty cycle between 15% to 75% whereas a CUT waveform typically hasa duty cycle greater than 75%. The off time allows the tissue to coolcreating some haemostasis. Accordingly, a BLEND waveform is used wherehaemostasis is required as tissue is cut. It will be evident to a personof skill in the art that these are examples only and that differentelectrosurgical generators may be configured to generate differentand/or additional waveforms.

In existing manual, as opposed to robotic, electrosurgical systems, thesurgeon can cause a driving electrosurgical signal with a particularwaveform (e.g. COAG, CUT or BLEND) to be provided to an electrosurgicalinstrument attached to the electrosurgical generator using controls(e.g. buttons) on the manual electrosurgical instrument or usingcontrols (e.g. foot pedals) connected to the electrosurgical generator.FIG. 3 illustrates an example manual monopolar electrosurgicalinstrument 302 that comprises at its distal end 304 an active electrode306 for achieving a surgical effect when activated by a drivingelectrosurgical signal. The manual monopolar electrosurgical instrument302 also comprises two activation buttons 308, 310 which can be used tocause the electrosurgical generator to provide a driving electrosurgicalsignal with a first waveform (e.g. a CUT waveform) and a drivingelectrosurgical signal with a second waveform (e.g. a COAG waveform)respectively to the electrosurgical instrument 302. The CUT button istypically coloured yellow and the COAG button is typically coloured blueto comply with specific standards.

FIG. 4 is used to explain how such a monopolar electrosurgicalinstrument 302 controls the operation of an electrosurgical generator402. As shown in FIG. 4 the electrosurgical instrument 302 is attachedto the electrosurgical generator 402 via a cable 404. Typically, thecable is integrated with the electrosurgical instrument 302 to form asingle disposable device. However, the cable 404 may not be integralwith the electrosurgical instrument, but the cable 404 may have aconnector at one end which is configured to engage a correspondingconnector of the electrosurgical instrument 302. In either case, thecable 404 typically comprises a connector at one end which is configuredto engage a corresponding connector of the electrosurgical generator402. This generator-end connector of the cable 404 may, for example. bea standard 3-pin Valleylab™ connector, such as that described in theValleylab™ FT10 Energy Platform User Guide.

The cable 404 carries three conductors or wires 410, 412, 414—an activewire 410 and two control wires 412, 414. The active wire 410 is used totransmit a driving electrosurgical signal generated by theelectrosurgical generator 402 to the electrosurgical instrument 302. Thecontrol wires 412, 414 are used to transmit activation signals generatedby the electrosurgical instrument 302 to the electrosurgical generator402.

The active wire 410 is electrically coupled to the active electrode 306of the electrosurgical instrument 302 so that any drivingelectrosurgical signal received on the active wire 410 is provided tothe active electrode 306. The two activation buttons 308, 310 of theelectrosurgical instrument 302 are connected to corresponding switches406, 408. One port of each switch 406, 408 is coupled to the active wire410 and the other port of each switch 406, 408 is coupled to one of thecontrol wires 412, 414. Specifically, a second port of the first switch406 is coupled to the first control wire 412, and the second port of thesecond switch 408 is coupled to the second control wire 414. When anactivation button 308, 310 is depressed the corresponding switch 406,408 is activated which connects the active wire 410 to the correspondingcontrol wire 412, 414 which sends a corresponding activation signal tothe electrosurgical generator 402. Specifically, when theelectrosurgical generator 402 is powered on, but is not active (i.e. isnot generating a driving electrosurgical signal) the electrosurgicalgenerator 402 outputs a weak signal on the active wire 410 and when aswitch 406, 408 is activated that weak signal is transmitted on thecorresponding control wire 412, 414.

When an activation signal is detected by control logic 416 of theelectrosurgical generator the control logic 416 causes RF generationlogic 418 of the electrosurgical generator 402 to output a drivingelectrosurgical signal on the active wire 410 with a waveform associatedwith that activation signal. For example, the first activation button308 may be associated with a CUT waveform such that when the userpresses or activates the first activation button 308 a first activationsignal is transmitted to the electrosurgical generator 402 on the firstcontrol wire 412 which causes the electrosurgical generator 402 tooutput a driving electrosurgical signal with a CUT waveform on theactive wire 410. The second activation button 310 may be associated witha COAG waveform such that when the user presses or activates the secondactivation button 310 a second activation signal is transmitted to theelectrosurgical generator 402 on the second control wire 414 whichcauses the electrosurgical generator 402 to output a drivingelectrosurgical signal with a COAG waveform on the active wire 410. Inthis example, a separate return electrode 420 is directly connected tothe electrosurgical generator 402 via a separate cable 422.

Instead of having the activation buttons on the electrosurgicalinstrument itself there may be a foot pedal system which allows thesurgeon, or other user, to cause an electrosurgical generator to providea driving electrosurgical signal with one waveform or another to anelectrosurgical instrument attached to the electrosurgical generator. Insome cases, using a separate foot pedal system is preferred as itreduces the complexity of the electrosurgical instrument. FIG. 5illustrates an example foot pedal system 502 comprising a first footpedal 504 and a second foot pedal 506 which can be used to cause anelectrosurgical generator to provide a driving electrosurgical signalwith a first waveform (e.g. a CUT waveform) and a second waveform (e.g.a COAG waveform) respectively to an electrosurgical instrument attachedto the electrosurgical generator. FIG. 6 is used to explain how such afoot pedal system 502 can be used to control the operation of anelectrosurgical generator 402 and an electrosurgical instrument 602.

The foot pedal system 502 is connected to the electrosurgical generator402 via a cable 604. The cable 604 may be integral with the foot pedalsystem 502 or may be connectable to the foot pedal system 502 via aconnector which engages a corresponding connector of the foot pedalsystem. In either case, the cable 604 typically comprises a connectorthat engages a corresponding connector of the electrosurgical generator404. In these cases the cable 604 carries three conductors or wires 610,612, 614—an active wire 610 and two control wires 612, 614.

The foot pedals 504 and 506 work in the same manner as the activationbuttons 308, 310 of FIGS. 3-4 . Specifically, the foot pedals 504, 506,like the activation buttons 308, 308, are each connected to a switch606, 608. One port of each switch 606, 608 is coupled to the active wire610 and a second port of each switch 606, 608 is coupled to one of thecontrol wires 612, 614. In particular, the second port of the firstswitch 606 is coupled to the first control wire 612 and the second portof the second switch 608 is coupled to the second control wire 614. Whena foot pedal 504, 506 is depressed the corresponding switch 606, 608 isactivated which connects the active wire 610 to the correspondingcontrol wire 612, 614 which causes a corresponding activation signal tobe transmitted to the electrosurgical generator 402.

When an activation signal is detected by the control logic 416 of theelectrosurgical generator 402, the control logic 326 causes the RFgeneration logic 418 of the electrosurgical generator 402 to output adriving electrosurgical signal with a waveform associated with thatactivation signal on the active wire 610. For example, the first footpedal 504 may be associated with a CUT waveform such that when the userpresses or activates the first foot pedal 504 a first activation signalis transmitted to the electrosurgical generator 402 on the first controlwire 612. When the electrosurgical generator 402 detects the firstactivation signal, the electrosurgical generator 402 outputs a drivingelectrosurgical signal with a CUT waveform on the active wire 610. Thesecond foot pedal 506 may be associated with a COAG waveform such thatwhen the user presses or activates the second foot pedal 506 a secondactivation signal is transmitted to the electrosurgical generator 402 onthe second control wire 614. When the electrosurgical generator 402detects the second activation signal, the electrosurgical generator 402outputs a driving electrosurgical signal with a COAG waveform on theactive wire 610. In this example, a cable comprising a single wire usedto carry the driving electrosurgical signal is then connected to theactive electrode 616 of the electrosurgical instrument 602. Like theexample in FIG. 4 , a separate return electrode 420 is directlyconnected to the electrosurgical generator 402 via a separate cable 422.

While the activation buttons 308, 310 and foot pedals 504, 506 describedabove with respect to FIGS. 3-6 provide convenient and safe means foractivating an electrosurgical instrument in a manual electrosurgicalsystem where a surgeon, or other user, holds the electrosurgicalinstrument during surgery, they are typically not suitable or notconvenient for activating an electrosurgical instrument in a roboticelectrosurgical system. Specifically, robotic electrosurgical systemstypically comprise a plurality of robotic arms, each of which can beattached to a different surgical instrument. A surgeon, or other user,can dynamically control any of the arms (and thus any of the surgicalinstruments attached thereto) via one or more input controllers (e.g.hand controllers) of a central command interface.

If an electrosurgical instrument in a robotic electrosurgical systemcomprised one or more activation buttons, as described with respect toFIGS. 3-4 , the surgeon would either have to move away from the commandinterface to depress the appropriate button on the instrument, or, thesurgeon, or other user, would have to instruct another person to do so,which may be unsafe (e.g. depressing the button may cause the instrumentto move to an undesired position in the patient) and may causeunnecessary delays and errors. If, alternatively, a foot pedal system isconnected to each electrosurgical generator, since there may be multiplegenerators that control different electrosurgical instruments thesurgeon, or other user, may have to manually confirm that the correctpedal system is used. It would be much more convenient and safe if thesurgeon, or other user, were able to activate an electrosurgicalinstrument attached to a robot arm via the command interface.Specifically, not only would it be more convenient to activateelectrosurgical instruments from the command interface, but the systemcould ensure that the desired electrosurgical instrument was beingactivated.

The embodiments described below are provided by way of example only andare not limiting of implementations which solve any or all of thedisadvantages of electrosurgical systems.

SUMMARY

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key features or essential features of the claimedsubject matter, nor is it intended to be used to limit the scope of theclaimed subject matter.

Described herein are electrosurgical connection units for a surgicalrobot arm to connect an electrosurgical instrument attached to the armto an electrosurgical generator. The electrosurgical connection unitsinclude an input port connectable to the electrosurgical generator, theinput port configured to receive a driving electrosurgical signal andoutput one or more activation signals; an output port connectable to theelectrosurgical instrument, the output port configured to output thedriving electrosurgical signal received on the input port; one or moreactivation switch units, wherein activation of an activation switch unitcauses an activation signal to be output from the input port indicatinga driving electrosurgical signal with a desired waveform is to beactivated; and a control unit configured to selectively activate one ofthe one or more activation switch units in response to a control signal.

A first aspect provides an electrosurgical connection unit for asurgical robot arm, the electrosurgical connection unit comprising: aninput port connectable to an electrosurgical generator, the input portconfigured to receive a driving electrosurgical signal and output one ormore activation signals; an output port connectable to anelectrosurgical instrument, the output port configured to output thedriving electrosurgical signal received on the input port; one or moreactivation switch units, wherein activation of an activation switch unitcauses an activation signal to be output from the input port indicatinga driving electrosurgical signal with a desired waveform is to beactivated; and a control unit configured to selectively activate one ofthe one or more activation switch units in response to a control signal.

The input port may be coupled to an active wire for receiving thedriving electrosurgical signal and one or more control wires fortransmitting an activation signal, and when an activation switch unit isactivated the active wire is connected to one of the one or more controlwires to generate the activation signal.

Each activation switch unit may comprise one or more switches in serieswherein one end of the series of switches is coupled to the active wireand the other end of the series of switches is coupled to one of the oneor more control wires.

At least one of the activation switch units may comprise at least twoswitches in series.

The one or more activation switch units may comprise a first activationswitch unit and a second activation switch unit.

When the input port is connected to an electrosurgical generator,activating the first activation switch unit may cause a first activationsignal to be transmitted to the electrosurgical generator which causesthe electrosurgical generator to output a driving electrosurgical signalwith a first waveform, and activating the second activation switch unitcauses a second activation signal to be transmitted to theelectrosurgical generator which causes the electrosurgical generator tooutput a driving electrosurgical signal with a second waveform.

The desired waveform may be one waveform of a plurality of waveformssupported by the electrosurgical generator. The plurality of waveformssupported by the electrosurgical generator may comprise a cuttingwaveform for producing a cutting effect and a coagulating waveform forproducing a coagulating effect.

The input port may be configured to receive a single cable over whichthe driving electrosurgical signal is received from the electrosurgicalgenerator and the one or more activation signals are transmitted to theelectrosurgical generator.

The output port may be configured to receive a cable over which thedriving electrosurgical signal is transmitted to the electrosurgicalinstrument.

The output port may be further configured to receive a returnelectrosurgical signal from the electrosurgical instrument or a returnelectrode, and the input port is configured to output a returnelectrosurgical signal received on the output port.

The return electrosurgical signal may also be transmitted to theelectrosurgical generator over the single cable received by the inputport.

The input port may be further configured to receive a second cable overwhich the return electrosurgical signal is transmitted to theelectrosurgical generator.

The output port may be configured to receive a second cable over whichthe return electrosurgical signal is received from a return electrode.

The control unit may be configured to activate an activation switch unitby outputting one or more signals that cause the activation switch unitto be activated.

The electrosurgical connection unit may further comprise an isolationdevice that forms an isolation barrier between the one or moreactivation switch units and the control unit.

The isolation device may be a digital isolator.

The electrosurgical connection unit may further comprise an alternatingcurrent coupling circuit situated between the control unit and each ofthe one or more activation switch units, each alternating currentcoupling circuit configured to receive a signal output by the controlunit and generate a direct current filtered version of the signal.

The electrosurgical connection unit may further comprise a measurementunit configured to measure a parameter of an activation switch unit andoutput measurement information to the control unit, the measurementinformation enabling a determination to be made as whether theactivation switch unit is operating as expected.

The measurement unit may be an impedance measurement device configuredto measure an impedance across the activation switch unit

The electrosurgical connection unit may further comprise a capacitanceemulation unit configured to present a predetermined capacitance to theelectrosurgical generator when the electrosurgical generator isconnected to the input port and activation of an activation switch unitof the one or more activation switch units causes an activation signalto be transmitted to the electrosurgical generator.

The control unit may be configured to generate a token comprisinginformation indicating a time at which the token was generated andtransmit the token to an external computing device, and the controlsignal is a modified version of the token that further comprisesinformation indicating the desired waveform.

The control unit may be configured to only activate an activation switchunit of the one or more activation switch units in response to receivingthe modified version of the token when at the time the modified versionof the token is received at the control unit an elapsed time since thetoken was generated is less than a threshold.

A second aspect provides a surgical robot arm comprising theelectrosurgical connection unit of the first aspect.

The electrosurgical connection unit may be integral with the surgicalrobot arm

The electrosurgical connection unit may be removably attached to thesurgical robot arm.

A third aspect provides a surgical robotic system comprising: thesurgical robot arm of the second aspect; an electrosurgical generatorconnected to the input port of the electrosurgical connection unit; andan electrosurgical instrument connected to the output port of theelectrosurgical connection unit.

A fourth aspect provides a method of activating an electrosurgicalinstrument attached to a surgical robot arm, the method comprising:generating, at a surgical robot arm control unit, a token comprisinginformation indicating a time at which the token was generated;transmitting the token from the surgical robot arm control unit to anexternal computing device; receiving the token at the external computingdevice; in response to the external computing device receiving inputindicating that the electrosurgical instrument is to be activated,transmitting a modified version of the received token to the surgicalrobot arm control unit, the modified version of the token indicatingthat the electrosurgical instrument is to be activated; and if thesurgical robot arm control unit receives the modified version of thetoken within a threshold amount of time from when the token wasgenerated, outputting one or more signals that cause the electrosurgicalinstrument to be activated.

The method may further comprise periodically incrementing a rollingcounter at the surgical robot arm control unit, and the informationindicating the time at which the token was generated comprises a valueof the counter at the time the token was generated.

The method may further comprise comparing the information in themodified version of the token indicating the time at which the token wasgenerated to a current value of the counter to determine whether themodified version of the token was received within the threshold amountof time from when the token was generated.

The token may further comprise information uniquely identifying thesurgical robot arm, and the method may further comprise determiningwhether the modified version of the token comprises the informationuniquely identifying the surgical robot arm, and only outputting the oneor more signals it is determined that the modified version of the tokencomprises the information uniquely identifying the surgical robot arm.

The token may further comprise validation information indicating whetherthe token is valid, and the method may further comprise determining fromthe validation information in the modified version of the token if themodified version of the token is valid, and only outputting the one ormore signals when it is determined that the modified version of thetoken is valid.

The validation information may be an error detection code.

The validation information may be a cyclic redundancy check code.

The method may further comprise, determining, at the external computingdevice, whether the modified version of the token is valid from thevalidation information; and only transmitting the modified version ofthe token to the surgical robot arm control unit when it is determinedthat the modified version of the token is valid.

The modified version of the token may comprise modified validationinformation.

The modified version of the token may comprise information indicating awaveform of a driving electrosurgical signal to activate theelectrosurgical instrument.

The waveform may be one of a monopolar coagulation waveform, a monopolarcut waveform, a bipolar coagulation waveform, a bipolar cut waveform anda blend waveform.

The one or more signals output by the surgical robot arm control unitmay cause the electrosurgical instrument to be activated by a drivingelectrosurgical signal with the waveform indicated in the modifiedversion of the token.

The method may further comprise determining whether the electrosurgicalinstrument supports the waveform indicated in the modified version ofthe token, and only transmitting the modified version of the token tothe surgical robot arm control unit if it is determined that theelectrosurgical instrument supports the waveform indicated in themodified version of the token.

The method may further comprise determining whether the surgical robotarm is currently being controlled by a user, and only transmitting themodified token to the surgical robot arm control unit if it isdetermined that the surgical robot arm is currently being controlled bya user.

The modified version of the token may be transmitted from the externalcomputing device to the surgical robot arm control unit via one or moreprocessors, and the method may further comprise, if any of the one ormore processor detects a non-electrosurgical activation state when themodified version of the token is received at that processor, discardingor invalidating the modified version of the token.

The external computing device may receive input indicating that theelectrosurgical instrument is to be activated when a user activates aninput on a device used to control the surgical robot arm and themodified version of the token is only transmitted to the surgical robotarm control unit if it is detected that the device is currently beingused to control the surgical robot arm.

The method may further comprise, in response to receiving the modifiedversion of the token, determining at the surgical robot arm control unitwhether the electrosurgical instrument and/or the surgical robot arm arein a suitable state for electrosurgical activation, and the one or moresignals are only output if it is determined that the electrosurgicalinstrument and/or surgical robot arm are in a suitable state forelectrosurgical activation.

The one or more control signals output by the surgical robot arm controlunit may be provided to an activation switch unit which causesactivation of the activation switch unit, wherein activation of theactivation switch unit causes an activation signal to be transmitted toan electrosurgical generator.

The one or more signals output by the surgical robot arm control unitmay comprise an oscillating signal.

The one or more signals output by the surgical robot arm control unitmay comprise a square wave.

A fifth aspect provides a system to activate an electrosurgicalinstrument attached to a surgical robot arm, the system comprising: anexternal computing device configured to: receive a token from a surgicalrobot arm control unit, the token comprising information indicating atime at which the token was generated by the surgical robot arm controlunit; and in response to receiving input indicating that theelectrosurgical instrument is to be activated, transmit a modifiedversion of the token to the surgical robot arm control unit, themodified version of the token indicating that the electrosurgicalinstrument is to be activated; and the surgical robot arm control unitin communication with the external computing device, the surgical robotarm control unit configured to: receive the modified version of thetoken; and in response to the modified version of token being receivedwithin a threshold amount of time from when the token was generated,outputting one or more signals that cause the electrosurgical instrumentto be activated.

The above features may be combined as appropriate, as would be apparentto a skilled person, and may be combined with any of the aspects of theexamples described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples will now be described in detail with reference to theaccompanying drawings in which:

FIG. 1 is a schematic diagram of an example surgical robot performing asurgical procedure;

FIG. 2 is a schematic diagram of an example surgical instrument;

FIG. 3 is a schematic diagram of an example monopolar electrosurgicalinstrument with two activation buttons;

FIG. 4 is a block diagram of an example electrosurgical systemcomprising the monopolar electrosurgical instrument of FIG. 3 , anelectrosurgical generator and a return electrode;

FIG. 5 is a schematic diagram of an example foot pedal system that canbe used to control an electrosurgical generator;

FIG. 6 is a block diagram of an example electrosurgical systemcomprising the foot pedal system of FIG. 5 , a monopolar electrosurgicalinstrument, an electrosurgical generator and a return electrode;

FIG. 7 is a schematic diagram of an example surgical robot systemincluding a robot arm comprising an electrosurgical connection unit;

FIG. 8 is a block diagram of an example electrosurgical systemcomprising a first example electrosurgical connection unit for amonopolar electrosurgical instrument;

FIG. 9 is a block diagram of a second example electrosurgical connectionunit for a monopolar electrosurgical instrument;

FIG. 10 is block diagram of an example electrosurgical system comprisinga third example electrosurgical connection unit for a monopolarelectrosurgical instrument;

FIG. 11 is a block diagram of an example electrosurgical systemcomprising an example electrosurgical connection unit for a bipolarelectrosurgical instrument;

FIG. 12 is a flow diagram of an example method for selectivelyactivating activation switch units of an electrosurgical connectionunit;

FIG. 13 is a schematic diagram illustrating an example format of a tokenfor use in activating an electrosurgical instrument; and

FIG. 14 is a flow diagram of an example token-based method for remotelyactivating an electrosurgical instrument attached to a surgical robotarm.

The accompanying drawings illustrate various examples. The skilledperson will appreciate that the illustrated element boundaries (e.g.,boxes, groups of boxes, or other shapes) in the drawings represent oneexample of the boundaries. It may be that in some examples, one elementmay be designed as multiple elements or that multiple elements may bedesigned as one element. Common reference numerals are used throughoutthe figures, where appropriate, to indicate similar features.

DETAILED DESCRIPTION

The following description is presented by way of example to enable aperson skilled in the art to make and use the invention. The presentinvention is not limited to the embodiments described herein and variousmodifications to the disclosed embodiments will be apparent to thoseskilled in the art. Embodiments are described by way of example only.

Described herein are electrosurgical connection units for a surgicalrobot arm for connecting an electrosurgical instrument attached to thearm to an electrosurgical generator in a manner that allows theelectrosurgical instrument to be dynamically driven by a desiredwaveform. Specifically, the electrosurgical connection units describedherein comprise an input port connectable to an electrosurgicalgenerator and an output port connectable to an electrosurgicalinstrument attached to the arm. The electrosurgical connection unit isconfigured to receive a driving electrosurgical signal via the inputport and transmit one or more activation signals via the input port. Theinput port and the output port are connected such that any drivingelectrosurgical signal received on the input port is output on theoutput port. The electrosurgical connection units also comprise one ormore activation switch units. When an activation switch unit isactivated it causes an activation signal to be transmitted to theelectrosurgical generator via the input port. The activation signalindicates a driving electrosurgical signal with a desired waveform froma plurality of waveforms is to be activated by the electrosurgicalgenerator. The electrosurgical connection units also comprise a controlunit which is configured to activate one of the one or more activationswitch units in response to receiving one or more control signals (whichmay be generated in response to input from the surgeon or other userindicating that the electrosurgical instrument is to be activated by adriving electrosurgical signal with a desired waveform).

Reference is now made to FIG. 7 which shows an example surgical robotsystem 700 in which the electrosurgical connection units describedherein may be implemented. The system 700 comprises a robot arm 702which comprises an electrosurgical connection unit 703 for connecting anelectrosurgical instrument attached to the arm to an electrosurgicalgenerator.

The robot arm 702 extends from a proximal end attached to a base 704.The arm comprises a number of rigid links 706. The links are coupled byrevolute joints 708. The most proximal link 706 a is coupled to the baseby joint 708 a. It and the other links are coupled in series by furtherones of the joints 708. Suitably, a wrist 710 is made up of fourindividual revolute joints. The wrist 710 couples one link (706 b) tothe most distal link (706 c) of the arm. The most distal link 706 c isat the distal end of the arm and carries an attachment structure 717 fora surgical instrument 712. Each joint 708 of the arm has one or moremotors 714 which can be operated to cause rotational motion at therespective joint, and one or more position and/or torque sensors 716which provide information regarding the current configuration and/orload at that joint. The motors may be arranged proximally of the jointswhose motion they drive, so as to improve weight distribution. Forclarity, only some of the motors and sensors are shown in FIG. 7 . Thearm may be generally as described in our co-pending patent applicationPCT/GB2014/053523.

The arm terminates in an attachment structure 717 for interfacing withthe instrument 712. The instrument 712 may take the form described withrespect to FIG. 2 . The attachment structure 717 comprises a driveassembly for driving articulation of the instrument. Movable interfaceelements of the drive assembly interface mechanically engagecorresponding movable interface elements of the instrument interface inorder to transfer drive from the robot arm to the instrument. Oneinstrument is exchanged for another several times during a typicaloperation. Thus, the instrument is attachable and detachable from therobot arm during the operation. Features of the drive assembly interfaceand the instrument interface aid their alignment when brought intoengagement with each other, so as to reduce the accuracy with which theyneed to be aligned by the user.

The instrument 712 comprises an end effector for performing anoperation. The end effector may take any suitable form. For example, theend effector may be smooth jaws, serrated jaws, a gripper, a pair ofshears, a needle for suturing, a camera, a laser, a knife, a stapler, acauteriser, a suctioner.

A variety of instrument types are known, each adapted to perform aparticular surgical function. One example type of instrument is anelectrosurgical instrument which is adapted to perform anelectrosurgical function. As described above, electrosurgery is thepassing of a high frequency (i.e. radio frequency) current throughtissue to cause a desired effect (e.g. cutting the tissue or coagulatingthe tissue). There are two types of electrosurgery—monopolar andbipolar. In monopolar electrosurgery the high frequency current passesthrough the patient from a live or active electrode of theelectrosurgical instrument to a separate return electrode placed on thepatient, which may also be referred to as a dispersive electrode pad, agrounding pad, a neutral electrode, a grounding mat, an indifferentelectrode or a patient electrode. In bipolar electrosurgery the activeand return electrodes are both within the electrosurgical instrument andthe current passes through the patient from the active electrode of theelectrosurgical instrument to the return electrode of theelectrosurgical instrument. An electrosurgical instrument which isconfigured for monopolar electrosurgery (e.g. an electrosurgicalinstrument that comprises an active electrode only) will be referred toherein as a monopolar electrosurgical instrument, and an electrosurgicalinstrument which is configured for bipolar electrosurgery (e.g. anelectrosurgical instrument that comprises both an active electrode and areturn electrode) will be referred to herein as a bipolarelectrosurgical instrument.

As described with respect to FIG. 2 the instrument comprises anarticulation between the instrument shaft and the end effector. Thearticulation comprises several joints which permit the end effector tomove relative to the shaft of the instrument. The joints in thearticulation are actuated by driving elements, such as cables. Thesedriving elements are secured at the other end of the instrument shaft tothe interface elements of the instrument interface. Thus, the robot armtransfers drive to the end effector as follows: movement of a driveassembly interface element moves an instrument interface element whichmoves a driving element which moves a joint of the articulation whichmoves the end effector.

Controllers for the motors, torque sensors and encoders are distributedwith the robot arm. The controllers are connected via a communicationbus to a robot control unit 718. The robot control unit 718 comprises aprocessor 720 and a memory 722. Memory 722 stores in a non-transient waysoftware that is executable by the processor 720 to control theoperation of the motors 714 to cause the arm 702 to operate in themanner described herein. In particular, the software can control theprocessor 720 to cause the motors (for example via distributedcontrollers) to drive in dependence on inputs from the sensors 716 andfrom a surgeon command interface 724. The robot control unit 718 iscoupled to the motors 714 for driving them in accordance with outputsgenerated by execution of the software. The robot control unit 718 iscoupled to the sensors 716 for receiving sensed input from the sensors,and to the command interface 724 for receiving input from it. Therespective couplings may, for example, each be electrical or opticalcables, or may be provided by a wireless connection. The commandinterface 724 comprises one or more input devices whereby a user canrequest motion of the end effector in a desired way. The input devicescould, for example, be manually operable mechanical input devices suchas hand controllers or joysticks, or contactless input devices such asoptical gesture sensors. The software stored in memory 722 is configuredto respond to those inputs and cause the joints of the arm andinstrument to move accordingly, in compliance with a pre-determinedcontrol strategy. The control strategy may include safety features whichmoderate the motion of the arm and instrument in response to commandinputs. Thus, in summary, a surgeon at the command interface 724 cancontrol the instrument 712 to move in such a way as to perform a desiredsurgical procedure. The robot control unit 718 and/or the commandinterface 724 may be remote from the arm 702.

The robot arm 702 also comprises an electrosurgical connection unit 703for connecting an electrosurgical instrument 712 attached to the arm toan electrosurgical generator 726. As described above, electrosurgicalinstruments are driven by a high frequency current which may be referredto herein as a driving electrosurgical signal. The drivingelectrosurgical signals are generated by an electrosurgical generator726, which may also be referred to as an electrosurgery generator,electrosurgical end unit, electrosurgery end unit, or ESU.Electrosurgical generators are generally capable of generating multipledifferent current waveforms to achieve different surgical effects. Forexample, many standard electrosurgical generators can be configured togenerate COAG, CUT and BLEND waveforms. The COAG waveform consists ofbursts of radio frequency, which when used at a low power setting causesa desiccation effect, and when used at a high-power setting causes afulguration effect. The CUT waveform is a continuous waveform at a lowervoltage, but higher current than COAG, which causes the tissue to becut. A BLEND waveform is essentially a CUT waveform with a lower dutycycle. For example, the duty cycle of a CUT waveform is typicallybetween 15% and 75%, whereas a CUT waveform typically has a duty cyclegreater than 75%. The off time allows the tissue to cool creating somehaemostasis. Accordingly, a BLEND waveform is typically used wherehaemostasis is required as tissue is cut. It will be evident to a personof skill in the art that these are examples only and that differentelectrosurgical generators may be configured to generate differentand/or additional waveforms.

The electrosurgical generator 726 comprises any suitable means forconfiguring the waveforms that can be generated. For example, anelectrosurgical generator 726 may comprise a user interface thatcomprises, for example, switches, buttons, dials etc., which enable auser to configure each supported waveform (e.g. a CUT waveform, a COAGwaveform and a BLEND waveform). In other examples, the electrosurgicalgenerator 726 may be configured electronically, such as via a controlsignal transmitted to the electrosurgical generator from a computingdevice. For example, the electrosurgical generator 726 may be connectedto the robot control unit 718 and the waveforms configured by thecommand interface 724. The user may be able to configure, for example,the voltage and/or frequency of the waveform.

The electrosurgical generator 726 also comprises control logic 728 whichis configured to receive activation signals indicating which waveform ofthe plurality of supported waveforms are to be activated by theelectrosurgical generator 726. For example, where the electrosurgicalgenerator 726 can generate a driving electrosurgical signal with a CUTwaveform or a driving electrosurgical signal with a COAG waveform theelectrosurgical generator 726 may be configured to receive one or moreactivation signals indicating which of the CUT waveform and the COAGwaveform is to be used to generate the driving electrosurgical signal.In response to the control logic 728 detecting an activation signalindicating that a driving electrosurgical signal with a CUT waveform isto be activated the electrosurgical generator 726 (e.g. the RFgeneration logic 730) outputs a driving electrosurgical signal with aCUT waveform (as previously configured). Similarly, in response to thecontrol logic 728 detecting an activation signal indicating that adriving electrosurgical signal with a COAG waveform is to be activatedthe electrosurgical generator 726 (e.g. the RF generation logic 730)outputs a driving electrosurgical signal with a COAG waveform (aspreviously configured). In some cases, the electrosurgical generator 726may be configured to continue outputting a driving electrosurgicalsignal with the desired waveform so long as it detects the correspondingactivation signal (and a fault condition has not been detected), and tocease outputting a driving electrosurgical signal with the desiredwaveform as soon as it ceases to detect the corresponding activationsignal.

When an activation signal is detected by the control logic 728, inaddition to causing a driving electrosurgical signal with the desiredwaveform to be output, the control logic 728 may cause a feedback signalto be output to alert the user of the activation of a particularwaveform. The feedback may be in the form of visual feedback (e.g. anindicator light on a display panel of the electrosurgical generator 726)or audible feedback (e.g. a tone).

The electrosurgical connection unit 703 is configured to act as anintermediary between an electrosurgical instrument 712 attached to thearm 702 and an electrosurgical generator 726. Specifically, theelectrosurgical connection unit 703 is configured to selectivelytransmit activation signals to the electrosurgical generator indicatingthat the electrosurgical instrument attached to the arm is to beactivated by a driving electrosurgical signal with a particular waveform(of the plurality of waveforms supported by the electrosurgicalgenerator) in response to one or more control signals received from anexternal computing device. The control signals may be generated by, forexample, the robot control unit 718 in response to the surgeon or otheruser providing input via the command interface 724 indicating that theelectrosurgical instrument attached to the arm currently beingcontrolled is to be driven by a driving electrosurgical signal with adesired waveform. The electrosurgical connection unit 703 is alsoconfigured to receive any driving electrosurgical signal produced by theelectrosurgical generator in response to an activation signal andprovide the received driving electrosurgical signal to theelectrosurgical instrument attached to the arm. Example electrosurgicalconnection units 703 are described below with respect to FIGS. 8-11 .

The electrosurgical connection unit 703 may be integral with the arm 702or may be removably attached to the arm 702. The electrosurgicalconnection unit 703 may be removably attached to the arm 702 using anysuitable means such as, but not limited to, Velcro™, or gaffer tape.Although the electrosurgical connection unit 703 is shown in FIG. 7 asbeing attached to a middle link 706 b of the arm 702, theelectrosurgical connection unit 703 may be attached to any suitable partof the arm 702. For example, the electrosurgical connection unit 703 maybe connected to any link 706 a, 706 b, 706 c of the arm 702 or theelectrosurgical connection unit 703 may be connected to the base 704 ofthe arm 702. In some cases the base 704 may comprise or be attached to acart or trolley and the electrosurgical connection unit may be integralwith or removably attached to the cart. The arm 702 is typically coveredin a sterile drape during surgery. Where there is an opening in thedrape around the base 704 of the arm 702, attaching the electrosurgicalconnection unit 703 to the base 704 or the most proximal link 706 a maymake it easier to connect the electrosurgical connection unit 703 to theelectrosurgical generator 726 and/or the electrosurgical instrument 712via the opening in the drape. In some cases, components of theelectrosurgical connection unit 703 may be attached to different partsof the arm 702. For example, as described below, the electrosurgicalconnection unit may comprise an input port, and output port, one or moreactivation switches and a control unit. In some cases, the control unitmay be situated on a different part of the arm from the input port,output port, and activation switches.

Reference is now made to FIG. 8 which illustrates an exampleelectrosurgical connection unit 703 for connecting a monopolarelectrosurgical instrument to an electrosurgical generator 726. Theelectrosurgical connection unit 703 comprises an input port 802, anoutput port 804, a plurality of activation switch units 806, 808 and acontrol unit 810.

The input port 802 is connectable (directly or indirectly) to anelectrosurgical generator 726 so as to receive a driving electrosurgicalsignal generated by the electrosurgical generator 726 and to transmitone or more activation signals to the electrosurgical generator 726.Each activation signal indicates to the electrosurgical generator 726that a driving electrosurgical signal with a desired waveform of theplurality of waveforms supported by the electrosurgical generator 726 isto be activated. The input port 802 may be electrically coupled to aplurality of wires or conductors—an active wire or conductor 812 toreceive the driving electrosurgical signal from the electrosurgicalgenerator 726 and one or more control wires or conductors 814, 816 totransmit the activation signals(s) to the electrosurgical generator 726.In the example shown in FIG. 8 , there are two control wires 814, 816,one control wire 814 is configured to transmit a first activation signalto the electrosurgical generator 726 that indicates that a drivingelectrosurgical signal with a first waveform (e.g. a CUT waveform) is tobe activated and the other control wire 816 is configured to transmit asecond activation signal to the electrosurgical generator 726 thatindicates that a driving electrosurgical signal with a second waveform(e.g. a COAG waveform) is to be activated. However, it will be evidentto a person of skill in the art that this is an example only and thatthere may be fewer than two control wires and/or more than two controlwires over which the activation signal(s) are transmitted.

The input port 802 may be configured to receive one or more cables overwhich the driving electrosurgical signal is received from theelectrosurgical generator 726 and the activation signals are transmittedto the electrosurgical generator 726. In some cases, the input port 802may be configured to receive a single cable over which the drivingelectrosurgical signal and the activation signals are transmitted. Inother cases, the input port 802 may be configured to receive a pluralityof cables over which the driving electrosurgical signal and theactivation signal are transmitted. For example, there may be one cableper signal. In some cases, the input port 802 may comprise one connectorfor each expected cable that is configured to engage a correspondingconnector of the cable. In some cases, the connector(s) of the inputport 802 may be male connectors which are configured to receive acorresponding female connector of a cable connected directly orindirectly to the electrosurgical generator 726.

The output port 804 is connectable (directly or indirectly) to anelectrosurgical instrument 712 attached to the arm 702. The output port804 is electrically connected or coupled to the active wire 812 so thatany driving electrosurgical signal received from the electrosurgicalgenerator 726 via the input port 802 is output on the output port 804.

The output port 804 may be configured to receive a cable over which thedriving electrosurgical signal is transmitted to the electrosurgicalinstrument 712. In some examples, the output port 804 comprises a femaleconnector configured to engage a corresponding male connector connectedto a cable which is connected directly or indirectly to theelectrosurgical instrument 712.

Each activation switch unit 806, 808 is configured to, when activated,cause an activation signal to be transmitted via the input port 802 toindicate to the electrosurgical generator 726 that a drivingelectrosurgical signal with a desired waveform, of the plurality ofwaveforms supported by the electrosurgical generator 726, is to beactivated. In response to detecting the activation signal, theelectrosurgical generator 726 outputs a driving electrosurgical signalwith the desired waveform. The input port 802 then receives the drivingelectrosurgical signal with the desired waveform and outputs thereceived signal on the output port 804.

In the example of FIG. 8 there are two activation switch units 806 and808. When the first activation switch unit 806 is activated a firstactivation signal is transmitted over the first control wire 814 whichindicates to the electrosurgical generator 726 that a drivingelectrosurgical signal with a first desired waveform (e.g. CUT waveform)is to be activated. In response to detecting the first activationsignal, the electrosurgical generator 726 generates and outputs adriving electrosurgical signal with the desired waveform (e.g. CUTwaveform). When the second activation switch unit 808 is activated asecond activation signal is transmitted over the second control wire 816which indicates to the electrosurgical generator 726 that a drivingelectrosurgical signal with a second desired waveform (e.g. COAGwaveform) is to be activated. In response to detecting the secondactivation signal the electrosurgical generator 726 generates andoutputs a driving electrosurgical signal with the second desiredwaveform (e.g. COAG waveform). However, it will be evident to a personof skill in the art that this is an example only and that there may bemore than two activation switch units or only one activation switch unit(see, for example, FIG. 11 ).

In the example shown in FIG. 8 , a first port of each activation switchunit 806, 808 is connected to the active wire 812 and a second port ofeach activation switch unit 806, 808 is connected to one of the controlwires 814, 816. Specifically, the second port of the first activationswitch unit 806 is connected to the first control wire 814, and thesecond port of the second activation switch unit 808 is connected to thesecond control wire 816. In this example, when an activation switch unit806, 808 is activated the active wire 812 is electrically connected tothe corresponding control wire 814, 816 (i.e. the active wire 812 isshorted to the corresponding control wire 814, 816) which causes anactivation signal to be transmitted to the electrosurgical generator onthat control wire 814, 816. In other words, when an activation switchunit 806, 808 is activated it closes a control loop extending betweenthe electrosurgical generator 726 and the electrosurgical connectionunit 703 which can be detected by the electrosurgical generator 726(e.g. control logic 728 of the electrosurgical generator 726). When theelectrosurgical connection unit 703 is configured to generate theactivation signals in this manner the electrosurgical connection unit703 can be connected to existing electrosurgical generators, such asthose described above with reference to FIGS. 4 and 6 , which areconfigured to detect activation signals by detecting a closure of acontrol loop.

Each activation switch unit 806, 808 comprises at least one switch 807,809 connected in series with the first port and the second port of theactivation switch unit 806, 808. When an activation switch unit 806, 808is activated all the switch(es) 807, 809 of the activation switch unit806, 808 are placed in the closed position so as to connect the firstand second ports of the activation switch unit 806, 808. In the exampleof FIG. 8 each activation switch unit 806, 808 comprises one switch 807,809. However, in other examples, one or more of the activation switchunits 806, 808 may comprise a plurality of switches in series. Havingmultiple switches in series prevents an activation signal inadvertentlybeing transmitted by the electrosurgical connection unit 703 to theelectrosurgical generator when one of the switches fails in the closedposition, causing a driving electrosurgical signal to be inadvertentlyprovided to an electrosurgical instrument attached to the arm. Causingan electrosurgical instrument to be inadvertently activated could beextremely dangerous. Each switch may be implemented, for example, by arelay, such as an electromechanical relay (EMR) or a solid-state relay(SSR). As is known to those of skill in the art, in electromechanicalrelays (EMR), contacts are opened or closed by a magnetic force. Withsolid-state relays (SSR), there are no contacts and switching iselectronic.

The control unit 810 is configured to control the activation switchunits 806, 808 in response to control signals received from an externalcomputing device. Specifically, the control unit 810 is configured toreceive control signals from an external computing device andselectively activate one of the activation switch units 806, 808 inresponse to the control signals so as to cause an electrosurgicalinstrument attached to the arm to be driven by a driving electrosurgicalsignal with a desired waveform. The control signals may be generated byan external computing device in response to input received from asurgeon or another user indicating that the electrosurgical instrumentattached to a particular arm is to be activated by a drivingelectrosurgical signal with a particular waveform. In some cases, thecontrol signals may be generated by the robot control unit 718 inresponse to input received from the surgeon or another user via thecommand interface 724 indicating that the electrosurgical instrumentattached to a particular arm is to be activated by a drivingelectrosurgical signal with a particular waveform.

In these cases, the command interface 724 may comprise one or more inputdevices that allow the user to indicate that an electrosurgicalinstrument that a user is currently controlling is to be activated by adriving control signal and what type of waveform. For example, where thecommand interface 724 comprises manually operable input devices such ashand controllers or joysticks, the hand controllers or joysticks maycomprise one or more buttons, switches, or the like that allow the userto indicate that the electrosurgical instrument that is currently beingcontrolled is to be activated by a driving electrosurgical signal andthe type of waveform. For example, the hand controllers or joysticks maycomprise a CUT button and a COAG button which the user can press toindicate that the electrosurgical instrument is to be activated by a CUTwaveform or a COAG waveform. In some cases, to avoid a drivingelectrosurgical signal from being transmitted to an electrosurgicalinstrument by inadvertent contact with such buttons or switches, the oneor more buttons or switches may only be able to cause a drivingelectrosurgical signal to be transmitted to the electrosurgicalgenerator if the robot control unit detects that a user is currentlygrasping the hand controllers or joysticks.

In other examples, when the user is controlling an electrosurgicalinstrument the user may be provided with one or more options on agraphical user interface displayed on a display screen that can beclicked, or otherwise selected, by the user to indicate that theelectrosurgical instrument is to be activated and the type of waveformthe electrosurgical instrument is to be activated with. For example, aCUT button and a COAG button may displayed on a display screen that canbe clicked, or otherwise selected, by the user to indicate that theelectrosurgical instrument is to be activated with a CUT waveform or aCOAG waveform.

In yet other examples, the command interface 724 may comprise acombination of the buttons and graphical user interface componentsdescribed above to allow the user to indicate that a particularelectrosurgical instrument is to be activated and the waveform to beused for the driving electrosurgical signal. For example, the userinterface may allow the surgeon, or other user, to indicate the type ofwaveform to be used for the driving electrosurgical signal and theelectrosurgical instrument to be activated, and the hand controller orjoysticks may comprise a single button which, when depressed, indicatesthat the selected electrosurgical instrument is to be activated with adriving electrosurgical signal with the selected waveform. In somecases, the hand controller or joystick may comprise one or more colouredLEDs near the activation button which indicates the selected waveform(e.g. a blue LED may be illuminated when a COAG waveform is selected anda yellow LED may be illuminated when CUT waveform is selected).

Thus, in addition to a surgeon being able to control the movement of aninstrument 712 attached to an arm 702 via the command interface 724,when that instrument is an electrosurgical instrument the surgeon mayalso be able to control, from the command interface 724, when thatelectrosurgical instrument 712 is activated and the type of waveform ofthe driving electrosurgical signal.

The control unit 810 may comprise a communications module 818, one ormore processors 820 and a memory 822. The communication module 818 isconfigured to receive control signals from the external computing device(e.g. robot control unit 718). The communications module 818 may beconfigured to receive the control signals from the external computingdevice (e.g. robot control unit 718) in any suitable manner such as, butnot limited to, electrically, optically or wirelessly. For example, insome cases, the communications module 818 may be coupled to a wiredcommunication network, such as, but not limited to, an Ethernet network,over which the communications module 818 receives the control signalsfrom the external computing device (e.g. robot control unit 718). Inother cases, the communications module 818 may be coupled to a wirelesscommunication network, such as, but not limited to, a Wi-Fi™ network ora NFC (Near Field Communication) network, over which the communicationsmodule 818 receives the control signals from the external computingdevice (e.g. robot control unit 718).

In some cases, in addition to being able to receive the control signalsfrom the external computing device (e.g. robot control unit 718) thecommunications module 618 may also be able to transmit data orinformation to the external computing device (e.g. robot control unit718). For example, as described in more detail below, theelectrosurgical connection unit 703 may also comprise an impedancemeasurement unit which is configured to measure the impedance across theactivation switch units 806, 808 and information related to the detectedimpedance(s) may be transmitted to the external computing device (e.g.robot control unit 718) via the communications module 818. Where thecommunications module 818 can receive information from, and transmitinformation to, the external computing device (e.g. robot control unit718) the communications module 818 may be described as a transceiver.

The memory 822 is configured to store computer-executable instructionsthat when executed by the one or more processors 820 cause the one ormore processors 820 to perform the functions described herein.Specifically, the one or more processors 820 are configured (by thecomputer-executable instructions) to analyse any control signal receivedby the communications module 818 and activate one or more of theactivation switches based on the analysis. The control signals areconfigured to indicate to the one or more processors 820 when anelectrosurgical instrument is to be activated by a drivingelectrosurgical signal and the waveform of the driving electrosurgicalsignal. Both the activation information and the waveform information maybe included in a single control signal or the activation information andthe waveform information may be included in different control signals(e.g. there may be a control signal that indicates that theelectrosurgical instrument is to be activated and a different controlsignal that indicates the waveform of the driving electrosurgicalsignal). The control signals may take any suitable form that isunderstood by the one or more processors 820. In some cases, asdescribed in more detail below, the control signals may be tokens.

The one or more processors 820 are configured to analyse any controlsignal, or set of control signals, received by the communications module818 to determine whether the electrosurgical instrument attached to thearm is to be activated and if the electrosurgical instrument attached tothe arm is to be activated the desired waveform of the drivingelectrosurgical signal. In response to determining from a receivedcontrol signal, or set of control signals, that the electrosurgicalinstrument is to be activated by a driving electrosurgical signal with aparticular waveform the one or more processors 820 may be configured toactivate the activation switch unit 806, 808 that will cause anactivation signal to be transmitted to the electrosurgical generator 726that indicates that the electrosurgical instrument is to be activated bya driving electrosurgical signal having that particular waveform.

For example, where there are two activation switch units 806, 808 andone activation switch unit 806 is configured to cause a first activationsignal to be transmitted to the electrosurgical generator whichindicates that the electrosurgical instrument is to be activated by adriving electrosurgical signal with a first waveform (e.g. CUTwaveform), and the other activation switch unit 808 is configured tocause a second activation signal to be transmitted to theelectrosurgical generator which indicates that the electrosurgicalinstrument is to be activated by a driving electrosurgical signal with asecond waveform (e.g. COAG waveform), if the one or more processors 820determine from a received control signal, or set of control signals,that the electrosurgical instrument attached to the arm is to beactivated by a driving electrosurgical signal with the first waveform(e.g. CUT waveform) the one or more processors may be configured toactivate the first activation switch unit 806, and if the one or moreprocessors 820 determine from a received control signal, or set ofcontrol signals, that the electrosurgical instrument is to be activatedby a driving electrosurgical signal with the second waveform (e.g. COAGwaveform) the one or more processors 820 may be configured to activatethe second activation switch unit 808.

In some cases, the one or more processors 820 may be configured toactivate a particular activation switch unit 806, 808 by outputting oneor more signals that cause all the switches 807, 809 of that activationswitch unit 806, 809 to be in a closed position. An example method forprocessing control signals received from an external computing device,which may be implemented by the one or more processors 820, is describedbelow with respect to FIG. 12 .

In this example, a separate return electrode 824 is directly connectedto the electrosurgical generator 726 via a separate cable 826.

Reference is now made to FIG. 9 which illustrates a second exampleelectrosurgical connection unit 903 for connecting a monopolarelectrosurgical instrument to an electrosurgical generator 726. Theexample electrosurgical connection unit 903 of FIG. 9 is the same as theelectrosurgical connection unit 703 of FIG. 8 except the electrosurgicalconnection unit 903 includes one or more further optional components.

As described above with respect to FIG. 8 , it could be quite dangerousif an activation switch unit 806, 808 of the electrosurgical connectionunit 903 failed such that it was stuck in an activated state (i.e. theswitches 807, 809 of the activation switch unit 806, 808 are stuck in aclosed position) because this would allow an activation signal to beinadvertently transmitted to the electrosurgical generator causing adriving electrosurgical signal to be inadvertently sent to anelectrosurgical instrument attached to the electrosurgical connectionunit 903. As a result, the electrosurgical connection unit may compriseone or more measurement units 902, 904 that are configured to measure aparameter of one or more activation switch units 806, 808 and transmitmeasurement information to the control unit 810 which can be used todetermine whether the activation switch unit 806, 808 is workingproperly.

In some examples, each measurement unit 902, 904 may be an impedancemeasurement unit configured to measure the impedance across one or moreactivation switch units 806, 808. In these cases, the impedancemeasurement unit may be electrically coupled to both the active wire andthe control wire of the relevant activation switch unit 806, 808 tomeasure the impedance between them. As is known to those of skill in theart, the impedance between two points of a circuit may be determined,for example, by applying a current or voltage at one point and measuringthe current or voltage at the other point. However, in other examples,the measurement unit(s) may be configured to measure another parameterof the activation switch units 806, 808, such as voltage or current.

In some cases, the one or more processors 820 may be configured tocontrol the operation of the measurement units 902, 904. For example,the one or more processors 820 may be configured to periodically placean activation switch unit 806, 808 in a deactivated state (i.e. a statein which the switches of the activation switch unit are in the openposition) when the electrosurgical generator is inactive (i.e. is notoutputting a driving electrosurgical signal) and then cause themeasurement unit to measure the desired parameter (e.g. impedance). Inthese cases, when the system is started up an initialisation test may beperformed to determine a benchmark measurement for the parameter (e.g.impedance) when the activation switch unit is in the deactivated state.This benchmark can then be compared against the measured parameter todetermine if any of the switches is erroneously in the closed position.

In addition, or alternatively, the one or more processors may beconfigured to periodically place an activation switch unit 806, 808 inan activated state (i.e. a state in which the switches of the activationswitch unit are in the closed position) when the electrosurgicalgenerator is inactive (i.e. not outputting a driving electrosurgicalsignal) and then cause the measurement unit 902, 904 to measure thedesired parameter (e.g. impedance). This measurement can be used todetermine if the electrosurgical generator is active when an activationsignal has not been transmitted to the electrosurgical generator.

In some cases, there may be one measurement unit 902, 904 per activationswitch unit 806, 808. For example, in FIG. 9 the electrosurgicalconnection unit 903 comprises a first measurement unit 902 that isconfigured to measure a parameter (e.g. impedance) of the firstactivation switch unit 806 and a second measurement unit 904 that isconfigured to measure a parameter (e.g. impedance) of the secondactivation switch unit 808. In other cases, such as where the activationswitch units 806, 808 comprise two or more switches in series, there maybe one measurement unit 902, 904 per switch. For example, where eachactivation switch unit 806, 808 comprises two switches in series theelectrosurgical connection unit 903 may comprise four measurementunits—a first measurement unit that measures a parameter (e.g.impedance) across the first switch of the first activation switch unit806, a second measurement unit that measures a parameter (e.g.impedance) across the second switch of the first activation switch unit806, a third measurement unit that measures a parameter (e.g. impedance)across the first switch of the second activation switch unit 808, and afourth measurement unit that measures a parameter (e.g. impedance)across the second switch of the second activation switch unit 808.However, in other cases there may be a single measurement unit that isconfigured to measure the parameter of multiple activation switch units806, 808.

In some cases, the one or more processors 820 may be configured toreceive the measurement information (e.g. the value of the measuredparameter) from the measurement unit and analyse the receivedmeasurement information to determine whether the measurement informationindicates that one or more of the activation switch units 806, 808is/are not operating as expected and/or the electrosurgical generator isnot operating as expected. For example, where the measurement unit is animpedance measurement unit, the one or more processors 820 may beconfigured to determine that one or more of the activation switch unitsis not operating as expected if an activation switch unit is expected tobe in a deactivated state (i.e. the switches thereof are in an openposition) yet there is no impedance across the activation switch unit.In response to determining that at least one of the activation switchunits 806, 808 is not operating as expected or the electrosurgicalgenerator is not operating as expected the one or more processors 820may be configured to send an error notification to the externalcomputing device (e.g. robot control unit 718) via the communicationsmodule 818.

In other cases, the one or more processors 820 may be configured tosimply receive the measurement information from the measurement unit(s)902, 904 and transmit the measurement information to the externalcomputing device (or another computing device), via the communicationsmodule 818, for further analysis and processing.

In some cases, the control logic 728 of the electrosurgical generator726 may be configured to detect an activation signal on a control lineby measuring the impedance on the line. The control logic 728 may alsobe able to detect a fault or failure based on the measured impedance. Inexisting manual, as opposed to, robotic electrosurgical systems, such asthose described above with respect to FIGS. 3-6 , wherein anelectrosurgical generator 726 is controlled by controls on anelectrosurgical instrument or a foot pedal system, the wires in thecables connecting the electrosurgical generator to the electrosurgicalinstrument (FIGS. 3-4 ), or foot pedal system (FIGS. 5-6 ) typicallypresent a significant capacitance to the electrosurgical generator 726and the control logic 728 is configured to detect an activation signaland identify a fault condition based on that amount of capacitance onthe line. In the robotic electrosurgical systems described hereinwherein the electrosurgical generator 726 is controlled by anelectrosurgical connection unit the wires in the cables connecting theelectrosurgical generator to the electrosurgical connection unit maypresent a different amount of capacitance to the electrosurgicalgenerator 726 compared to the wires in the cables used in manualelectrosurgical systems. In some examples, they may present lesscapacitance and in other examples, they may present more capacitance.For example, in some cases, the wires in the cables used in the roboticelectrosurgical systems described herein may be shorter than the wiresin the cables used in manual electrosurgical systems, and thus have lesscapacitance than the wires in the cables used in manual electrosurgicalsystems.

In these cases, to ensure that the electrosurgical generator 726 cancorrectly detect activation signals and to prevent the electrosurgicalgenerator 726 from erroneously detecting a fault condition on thecontrol line, the electrosurgical connection unit 903 may comprise oneor more capacitance emulation units 906, 908 each connected across oneof the control wires 814, 816 and the active wire 812. Each capacitanceemulation unit 906, 908 comprises one or more capacitors 910, 912 and/orone or more other capacitive components that are configured to emulatethe capacitance of the corresponding wire in the cables used in manualelectrosurgical system. For example, in FIG. 9 , there is a firstcapacitance emulation unit 906 that comprises a single capacitor 910across the first control wire 814 and the active wire 812; and a secondcapacitance emulation unit 908 that comprises a single capacitor 912across the second control wire 816 and the active wire 812. The totalcapacitance presented by each capacitance emulation unit 906, 908 may bebased on the difference between the capacitance presented by the wiresin the cables used to connect the electrosurgical connection unit 903 tothe electrosurgical generator 726 and the capacitance expected by theelectrosurgical generator 726. It will be evident to a person of skillin the art that this is an example only and that the capacitanceemulation units 906, 908 may take any suitable form that allows them toadd or subtract capacitance from a control line.

It may be advantageous to isolate the control unit 810 from the activewire 812 so that the high-powered driving electrosurgical signal carriedthereon does not cause damage to the one or more processors 820, memory822 and/or communications module 818 thereof. Specifically, it may bebeneficial to pass any wire connected to the control unit 810 and theactive wire 812 (directly or indirectly), such as the wires used totransmit signals to the activation switch units 806, 808 to causeactivation thereof, through an isolation barrier. The activation switchunits 806, 808 themselves provide one isolation barrier for the controlunit 810. However, in some cases this may not be sufficient to ensurethat the control unit 810 is protected from the high power drivingelectrosurgical signals.

Accordingly, in some cases, the electrosurgical connection unit 903 mayalso comprise an isolation device 914 that establishes an isolationbarrier between the control unit 810 and the active wire 812. In thesecases, any wire connected to the control unit 810 and the active wire812, such as the wires used to transmit signals to the activation switchunits to cause activation thereof, are connected to the isolation device914 and the data transmitted thereon is transferred to a correspondingwire connected (directly or indirectly) to the activation switch unit806, 808 and vice versa in a manner that ensures that any high poweredsignal transmitted or carried on the wire connected to the activationswitch unit is not transmitted or carried on the wire connected to thecontrol unit 810. The isolation device 914 may be any suitable isolationdevice such as a digital isolator or an opto-isolator. As is known tothose of skill in the art, digital isolators use semiconductor processtechnology to create either transformers or capacitors to transferelectrical signals between two isolated circuits, whereas opto-isolatorstransfer electrical signals between two isolated circuits using light.

Where the electrosurgical connection unit 903 also comprises one or moremeasurement units 902, 904, as described above, which transmitmeasurement information to the control unit 810, the wire on which themeasurement information is transmitted from the measurement unit 902,904 may be connected to the isolation device 914 and the informationcarried thereon may be transferred, by the isolation device 914, to acorresponding wire connected (directly or indirectly) to the controlunit 810 in such a manner that any high powered signal carried ortransmitted on the wire connected to the measurement unit 902, 904 isnot carried or transmitted on the wire connected (directly orindirectly) to the control unit 810.

In some cases, where there is at least one measurement unit 902, 904 theisolation device 914 may not provide sufficient protection for thecontrol unit 810. Accordingly, the electrosurgical connection unit 903may further comprise one or more additional isolation devices 916, 918between the measurement units 902, 904 and the control unit 810 toprovide double isolation for the measurement information signals, likethe double isolation that is provided for the control signal by theactivation switch units 806, 808 and the isolation device 914. In somecases, there may be an additional isolation device 916, 918 that issituated between each measurement unit 902, 904 and the isolation device914. For example, in the electrosurgical connection unit 903 of FIG. 9there is a first isolation device 916 that is situated between the firstmeasurement unit 902 and the isolation device 914, and a secondisolation device 918 that is situated between the second measurementunit 904 and the isolation device 914. In some cases, one or more of theadditional isolation devices may be an opto-isolator, which may also bereferred to as an optocoupler, photocoupler, or optical isolator. As isknown to those of skill in the art, an opto-isolator, in contrast to adigital isolator, transfers electrical signals between two isolatedcircuits by using light.

In some cases, the signal output by the control unit 810 to control, oractivate, an activation switch unit 806, 808 is an A/C (alternatingcurrent) or oscillating signal. In some examples the control unit 810 isconfigured to output a 500 Hz square wave. However, it will be evidentto a person of skill in the art that this is an example only. In thesecases, the electrosurgical connection unit 903 may comprise a conversioncircuit 919, 921 per activation switch unit 806, 808 that receives theA/C signal and groups the A/C pulses that form the A/C signal into asingle D/C (direct current) pulse, which is used to activate theactivation switch unit 806, 808. For example, the electrosurgicalconnection unit 903 of FIG. 9 comprises a first conversion circuit 919that receives the activation switch control signal generated by thecontrol unit 810 for the first activation switch unit 806 and convertsthat into a signal which activates the first activation switch unit 806;and a second conversion circuit 921 that receives the activation switchcontrol signal generated by the control unit 810 for the secondactivation switch unit 808 and converts that into a signal whichactivates the second activation switch unit 808.

Each conversion circuit 919, 921 may be implemented as an envelopedetector. Specifically, each conversion circuit 919, 921 may comprise aset of filters and diodes which are used to gradually charge a capacitorover a number of A/C pulses until the capacitor voltage switches theoutput of a comparator circuit. The comparator circuit may include anelement of hysteresis to prevent the output changing rapidly as thecapacitor charges and discharges small amounts between pulses. Thismeans that a single pulse is incapable of causing an output signal to beoutput from the conversion circuit. In other words, use of anoscillating signal to activate the activation switch units means that anactivation signal will not be transmitted to the electrosurgicalgenerator if a spurious constant or momentary signal is received. Only aseries of pulses in quick succession will cause an output signal to beoutput from the conversion circuit 919, 921.

Since a failure of the control unit 810 or the isolation device 914 islikely to result in an erroneous D/C signal (rather than an A/C signal)the electrosurgical connection unit 903 may comprise one or more A/Ccoupling circuits 920, 922 that precede one or more of the conversioncircuits 919, 921 to ensure that a failure of the control unit 810 orthe isolation device 914 cannot lead to inadvertent activation of theelectrosurgical instrument. More specifically, the electrosurgicalconnection unit 903 may comprise one or more A/C coupling circuits 920,922 to ensure that failure of the control unit 810 cannot lead toinadvertent activation of an activation switch unit 806, 808 whichcauses an activation signal being sent to the electrosurgical generator726 resulting in the electrosurgical generator 726 outputting a drivingelectrosurgical signal which inadvertently activates an electrosurgicalinstrument attached to the electrosurgical connection unit 903.

Each A/C coupling circuit 920, 922 is configured to receive a signal andfilter out the D/C (direct current) component of the signal and outputonly the A/C component of the signal. Each A/C coupling circuit 920, 922may comprise one or more capacitors. In some examples there may be anA/C coupling circuit situated between the control unit 810 (or theisolation device 914 if there is one) and each conversion circuit 919,921 which is configured to receive the corresponding activation switchcontrol signal from the control unit 810 (or the isolation device 914 ifthere is one) and A/C couple this signal to the conversion circuit 919,921 so that the conversion circuit 919, 921 receives an AC only signal(and any D/C component, erroneous or otherwise is removed). For example,the electrosurgical connection unit 903 shown in FIG. 9 comprises afirst A/C coupling circuit 920 situated between the isolation device 914and the first conversion circuit 919 which is configured to receive anactivation switch control signal generated by the control unit 810 andoutput the A/C component of that signal; and a second A/C couplingcircuit 922 situated between the isolation device 914 and the secondconversion circuit 921 which is configured to receive an activationswitch control signal generated by the control unit 810 and output theA/C component of that signal.

Reference is now made to FIG. 10 which illustrates a third exampleelectrosurgical connection unit 1003 for connecting a monopolarelectrosurgical instrument to an electrosurgical generator 726. Theexample electrosurgical connection unit 1003 of FIG. 10 is the same asthe electrosurgical connection unit 703 of FIG. 8 except that instead ofthe return electrode 330 being directly connected to the electrosurgicalgenerator 726, the return electrode is connected to the electrosurgicalconnection unit 1003 and the return electrosurgical signal received fromthe return electrode 330 is transmitted to the electrosurgical generatorvia the electrosurgical connection unit 1003. In this example, theoutput port 804 is configured to receive the return electrosurgicalsignal from the return electrode 824 and transmit the received returnelectrosurgical signal on a return wire 1004. The return wire 1004 isalso coupled to the input port 802 to allow any received returnelectrosurgical signal to be output on the input port 802.

As shown in FIG. 10 , the output port 804 of the electrosurgicalconnection unit 1003 may comprise a first connector that is configuredto engage a corresponding connector connected to a cable that isconnected to the electrosurgical instrument, and a second connector thatis configured to engage a corresponding connector connected to a cablethat is connected (directly or indirectly) to the return electrode. Inother examples, the output port 804 may comprise a single connector thatis configured to engage a corresponding connector that is connected totwo cables—one of which is connected (directly or indirectly) to theelectrosurgical instrument 712, and the other of which is connected(directly or indirectly) to the return electrode 824. The output port804 connector(s) may be female and the corresponding connectors may bemale or vice versa. In many cases, the input port 802 and the outputport 804 have opposite connectors to avoid electrosurgical devices frombeing plugged into or connected to the wrong port (i.e. to avoid anelectrosurgical instrument being inadvertently plugged into the inputport 802 and/or an electrosurgical generator 726 being inadvertentlyplugged into the output port 804). For example, in some cases the inputport 802 may have male connectors(s) and the output port 804 may havefemale connector(s).

As shown in FIG. 10 , the input port 802 of the electrosurgicalconnection unit 1003 may comprise a first connector that is configuredto engage a corresponding connector connected to a cable that isconnected (directly or indirectly) to the electrosurgical generator andis configured to carry the driving electrosurgical signal and controlsignals between the electrosurgical generator 726 and theelectrosurgical connection unit 1003; and a second connector that isconfigured to engage a corresponding connector connected to a cable thatis connected (directly or indirectly) to the electrosurgical generatorand is configured to carry the return electrosurgical signal from theelectrosurgical connection unit 1003 and the electrosurgical generator726. In other examples, the input port 802 may comprise a singleconnector that is configured to engage a corresponding connector that isconnected to a cable connected (directly or indirectly) to theelectrosurgical generator 726. In yet other examples, the input port 802may have any number of connectors that are configured to engagecorresponding connectors to enable the driving electrosurgical signal,the control signals and the return electrosurgical signal to betransmitted between the electrosurgical generator and theelectrosurgical connection unit 1003. The input port 802 connector(s)may be male and the corresponding connectors which engage the input port802 connectors may be female or vice versa.

Reference is now made to FIG. 11 which illustrates an exampleelectrosurgical connection unit 1103 for connecting a bipolarelectrosurgical instrument 1004 to an electrosurgical generator 726. Asdescribed above, a bipolar electrosurgical instrument comprises both anactive electrode 1106 and a return electrode 1108. The active electrode1106 is activated by a driving electrosurgical signal generated by theelectrosurgical generator 726 and the return electrode 1108 receives thereturn electrosurgical signal which is transmitted to theelectrosurgical generator 726. The active and return electrodes 1106,1108 may be made of, or may comprise, an electrically conductive typematerial, such as, for example, stainless steel. Some bipolarelectrosurgical instruments may not be capable of being driven bydriving electrosurgical signals with at least two differentpreconfigured waveforms. The bipolar instrument can either be activatedor not by the bipolar waveform configured on the electrosurgicalgenerator.

Accordingly, the electrosurgical connection unit 1103 of FIG. 11 is thesame as the electrosurgical connection unit 1003 of FIG. 10 where thereturn electrosurgical signal is received on the output port 804 andtransmitted out the input port 802 via a return wire 1004 connecting theinput port and the output port, except that the there is only oneactivation signal and thus only one control wire 816 and only oneactivation switch unit 808. When the activation switch unit 808 isactivated is sends an activation signal to the electrosurgical generator726 that indicates that a driving electrosurgical signal with a bipolarwaveform is to be activated which, when detected by the electrosurgicalgenerator 726 causes the electrosurgical generator 726 to output adriving electrosurgical signal with the bipolar waveform.

As described above with respect to FIG. 10 , the output port 804 maycomprise multiple connectors, one for each of the drivingelectrosurgical signal and the return electrosurgical signal, which areconfigured to engage corresponding connectors which are each connectedto a cable that is configured to carry one of the drivingelectrosurgical signal and the return electrosurgical signal. However,in most cases, since the driving electrosurgical signal is provided tothe electrosurgical instrument and the return electrosurgical signal isreceived from the electrosurgical instrument the output port 804comprises a single connector that is configured to engage acorresponding connector which is connected to a cable that is configuredto carry both the driving electrosurgical signal and the returnelectrosurgical signal.

Although the electrosurgical connection units 703, 903, 1003 of FIG.8-11 were described as supporting either a bipolar electrosurgicalinstrument or a monopolar electrosurgical instrument, other exampleelectrosurgical connection units may comprise components to support bothmonopolar electrosurgical instruments and bipolar electrosurgicalinstruments. Such electrosurgical connection units may comprise all thecomponents of the electrosurgical connection unit 703, 903, or 1003described above to support a monopolar electrosurgical instrument andall of the components of the electrosurgical connection unit 1103 ofFIG. 11 to support a bipolar electrosurgical instrument. For efficiencysuch electrosurgical connection units may comprise a single control unitthat controls all of the activation switch units (i.e. the activationswitch units that control activation of a monopolar electrosurgicalinstrument and the activation switch units the control activation of abipolar electrosurgical instrument). An electrosurgical instrumentattached to the arm may then be dynamically connected to the monopolarcomponents or the bipolar components depending on whether theelectrosurgical instrument is a monopolar electrosurgical instrument ora bipolar electrosurgical instrument.

Any of the electrosurgical connection units 703, 903, 1003, or 1103described above with respect to FIGS. 8, 9, 10, and 11 may comprise anycombination of the optional features described above with respect toFIG. 9 .

Reference is now made to FIG. 12 which illustrates an example method1200 which may be executed by the control unit 810 (e.g. the one or moreprocessors 820 of the control unit) to selectively active the activationswitch units. The method 1200 begins at block 1202 where the controlunit (e.g. the one or more processors 820 of the control unit)determines whether it has received (e.g. via the communications module818) a control signal or a set of control signals from an externalcomputing device. If the control unit (e.g. the one or more processors820) determines that it has received a control signal, or a set ofcontrol signals, then the method 1200 proceeds to block 1204. If,however, the control unit (e.g. the one or more processors 820)determines that is has not received a control signal or a set of controlsignals then the method 1200 proceeds back to block 1202.

At block 1204, the control unit 810 (e.g. the one or more processors820) determines whether the control signal or set of controls signalsindicate that an electrosurgical instrument attached to the arm is to beactivated by a driving electrosurgical signal. If the control unit 810(e.g. the one or more processors 820) determines that the control signalor set of control signals indicate that an electrosurgical instrumentattached to the arm is to be activated, then the method 1200 proceeds toblock 1206. If, however, the control unit 810 (e.g. the one or moreprocessors 820) determines that the control signal or set of controlsignals do not indicate that the electrosurgical instrument attached tothe arm is to be activated then the method 1200 proceeds back to block1202.

At block 1206, the control unit 810 (e.g. the one or more processors820) determines from the control signal, or set of control signals, thewaveform to be used for the driving electrosurgical signal. For example,where a monopolar electrosurgical instrument can be driven by a COAGwaveform or a CUT waveform the control unit 810 (e.g. the one or moreprocessors 820) may analyse the control signal, or set of controlsignals, to determine which waveform is to be used for the drivingelectrosurgical signal. Once the control unit 810 (e.g. the one or moreprocessors 820) has determined the waveform for the drivingelectrosurgical signal the method 1200 proceeds to block 1208.

At block 1208, the control unit 810 (e.g. one or more processors 820)identifies the activation switch unit to be activated to cause a drivingelectrosurgical signal with the determined waveform to be generated andgenerates one or more signals causing the identified activation switchunit to be activated (e.g. causes the switch(es) of the identifiedactivation switch unit to be in a closed position). For example, where amonopolar electrosurgical instrument can be driven by a COAG waveform ora CUT waveform the control unit 810 determines which of the activationswitch units is associated with the determined waveform and thengenerates one or more signals causing that activation switch unit to beactivated. In particular, if it is determined that the drivingelectrosurgical signal is to have a CUT waveform the control unit 810(e.g. the one or more processors 820) determines which activation switchunit is associated with a CUT waveform and then generates one or morecontrol signals to cause that activation switch unit to be activated.This causes a cut activation signal to be sent to the electrosurgicalgenerator, which when detected by the electrosurgical generator causesthe electrosurgical generator to output a driving electrosurgical signalwith a CUT waveform. The method 1200 then proceeds back to block 1202.

In some cases, the control unit 810 may be configured to output one ormore control signals that cause the appropriate activation switch unitto be activated for only a predetermined period (e.g. a fewmilliseconds) and then the method 1200 proceeds back to block 1202 wherethe control unit 810 determines whether it has received a new controlsignal (or set of control signals) indicating that the activation switchunit 806, 808 should continue to be activated. In this way the controlunit 810 only causes the appropriate activation switch unit 806, 808 tobe activated while the control unit 810 continues to receive a controlsignal (or a set of control signals) indicating that the activationswitch unit 806, 808 is to be activated. The predetermined period isgenerally quite short (e.g. a few milliseconds) to allow the controlunit 810 to respond quickly to a change from activation to deactivation(or vice versa) and from one type of activation to another (e.g. from adriving electrosurgical signal with a first waveform to a drivingelectrosurgical signal with a second waveform).

In some cases, the control unit 810 may be configured to implement themethod 1200 of FIG. 12 using a token-based approach to verify thelatency between the control unit 810 and the external computing device(e.g. robot control unit 718) generating the control signal(s) so thatstale control signals can be ignored. In the token-based approach thecontrol unit 810 is configured to generate a new token on a periodicbasis. For example, the control unit 810 may be configured to generate anew token at a frequency of 1 kHz. The token comprises information thatindicates the time at which the token was generated. For example, thecontrol unit 810 may be configured to update a rolling counter (e.g. a16-bit counter) each period and include the latest counter value in thetoken for that period. The token may also comprise information thatuniquely identifies the electrosurgical connection unit to which thecontrol unit 810 belongs (e.g. an electrosurgical connection unitidentifier (ID)).

In some cases, the token may also comprise validation information whichindicates whether the token is valid (e.g. has not been corrupted). Forexample, the token may also comprise a CRC (cyclic redundancy check)value based on some or all the information (e.g. fields) in the token.In some cases, each token may comprise an 8-bit CRC value.

Once the token has been generated, the control unit 810 transmits,directly or indirectly, (e.g. via the communication module 818) thegenerated token to the external computing device (e.g. robot controlunit 718) that generates the control signal for the electrosurgicalconnection unit.

The external computing device (e.g. robot control unit 718) receives thetoken and if the external computing device receives informationindicating that the electrosurgical instrument attached to theelectrosurgical connection unit identified in the token is to beactivated by a driving electrosurgical signal with a particular waveformthe token is modified to indicate the particular waveform to begenerated and the updated token is transmitted back to the control unit810. For example, as described above the command interface may comprisea display and one or more hand controllers or joysticks. The surgeon, orother user, may be able to select, via a graphical user interfacedisplayed on the display, the waveform to be generated and theelectrosurgical instrument to be activated. The surgeon, or other user,may then be able to indicate that the selected electrosurgicalinstrument is to be activated with the selected waveform by pressing anelectrosurgical activation button on the hand controller or joystick. Inthese examples, when the user presses the electrosurgical activationbutton the token related to the electrosurgical connection unit to whichthe selected arm is attached is updated with information indicating theselected waveform. Where the token includes validation information thevalidation information (e.g. CRC value) may be updated to reflect thewaveform information added to the token.

Where, for example, the electrosurgical generator supports threedifferent waveforms (e.g. a monopolar COAG waveform, a monopolar CUTwaveform, and a bipolar waveform) the token may comprise a two-bitwaveform field which indicates the selected waveform. For example, a“01” in the waveform field may indicate a monopolar COAG waveform, a“10” in the waveform field may indicate a monopolar CUT waveform, and a“11” may indicate a bipolar waveform.

In some cases, the external computing device (e.g. robot control unit718), or one or more other devices which receive the token prior to theelectrosurgical connection unit, may be configured to negate the tokenif one or more conditions for activating the selected electrosurgicalinstrument with the selected waveform are not met (or, alternatively,when a fault condition is detected). For example, the external computingdevice (e.g. robot control unit 718) and/or one or more other devicesmay be configured to negate a token if and when any of the followingconditions are detected: (i) the user is not currently controlling anarm that is connected to an electrosurgical instrument (e.g. the handcontroller or joystick on which the activation button was pressed is notactively connected to an arm that is connected to an electrosurgicalinstrument); (ii) the validation information indicates the token isinvalid (e.g. a CRC check fails); (iii) the electrosurgical instrumentattached to the selected arm does not support the selected waveform;(iv) the electrosurgical instrument, the arm or the electrosurgicalconnection unit is in a fault mode; and (v) the communications network(e.g. Ethernet network) over which the external computing device and theelectrosurgical connection unit communicate is faulty. It will beevident to a person of skill in the art that these are examples only andthat other conditions or fault states may cause a token to be negated.In some cases, negating the token may comprise setting all fields of thetoken (including the validation field where there is one) to zero whichmay be referred to as a zeroed token. In some cases, a negated token isnot passed on to the electrosurgical connection unit.

When the modified token is received at the electrosurgical connectionunit the electrosurgical connection unit is deemed to have received acontrol signal (block 1202 of method 1200). The control unit 810 thendetermines whether the modified token indicates that an electrosurgicalinstrument attached to the electrosurgical connection unit is to beactivated (block 1204 of method 1200). The control unit 810 maydetermine that the modified token indicates that an electrosurgicalinstrument attached to the electrosurgical connection unit is to beactivated (i) if the information in the token identifying theelectrosurgical connection unit that generated the token matches theidentifying information for the current electrosurgical connection unit;and (ii) if the information indicating when the token was generated(counter information) indicates that less than a predetermined amount oftime has elapsed since the token was generated. In some cases, thecontrol unit 810 may determine that less than a predetermined amount oftime has elapsed since the token was generated by comparing the counterinformation in the token to the current value of the counter (e.g. bycomputing the difference) and determining whether the difference exceedsa threshold. In some cases, the threshold may be set so that thepredetermined time is only a few milliseconds.

Where the token comprises validation information (e.g. a CRC value) thecontrol unit 810 may only determine that the token indicates that anelectrosurgical instrument attached to the electrosurgical connectionunit is to be activated if the above conditions are met and thevalidation information indicates that the token is valid (e.g. a CRCcheck passes).

If the control unit 810 determines that the token indicates that anelectrosurgical instrument attached to the electrosurgical connectionunit is to be activated then the control unit 810 analyses the token toidentify the desired waveform for the driving electrosurgical signal(block 1206 of method 1200).

Once the control unit 810 identifies the desired waveform for thedriving electrosurgical signal the control unit 810 identifies theswitch activation unit 806, 808 associated with the desired waveform andgenerates one or more signals causing the identified activation switchunit 806, 808 to be activated (e.g. causes the switches 807, 809 of theidentified activation switch unit 806, 808 to be in a closed position)(block 208 of method 1200). For example, as described above, the controlunit 810 may generate an oscillating signal (e.g. a square wave) for apredetermined period that causes the identified activation switch unitto be activated.

Reference is now made to FIG. 13 which illustrates an example format forsuch a token 1300, which may be referred to as an electrosurgery token.In the example of FIG. 13 , the token 1300 comprises four fields—asurgical robot arm identifier (ID) field 1302, a validation informationfield 1304, a flags field 1306, and a generation time information field1308. In one example, the token 1302 may be a 64-bit token wherein thesurgical robot arm ID field 1304 is 32 bits, the valid information fieldis 8 bits, the flags field 1306 is 8 bits and the generation timeinformation field 1308 is 16 bits. However, it will be evident to aperson of skill in the art that this is an example only and that othertokens with additional or alternative fields may be used and the tokenand the fields therein may have a different number of bits.

The surgical robot arm ID field 1302 is used to store information thatuniquely identifies the surgical robot arm associated with the controlunit 810 which generated the token. As described above, information thatuniquely identifies the surgical robot arm may comprise information thatuniquely identifies the electrosurgical connection unit to which thecontrol unit 810 belongs. In some cases, the control unit 810 maycomprise a unique serial number and the information uniquely identifyingthe surgical robot arm may be a serial number of the control unit 810.

The validation information field 1304 comprises information thatindicates whether the token is valid (e.g. has not been corrupted). Insome cases, the information indicating the token is valid may comprisean error detection code. For example, as described above, in some casesthe validation information may comprise a CRC value or code based onsome or all of the information (e.g. fields) in the token. As it couldbe disastrous to activate an electrosurgical instrument based on acorrupt token (e.g. it could cause the electrosurgical instrument to beactivated by the wrong waveform), using a CRC value to validate thetoken may provide an extra safety measure as it means that if any bit inthe entire token is corrupted the whole token will be invalid.

The flags field 1306 may be divided into two sub-fields—a reserved field1310 and an electrosurgical waveform field 1312, which may also bereferred to as an electrosurgical mode field. The electrosurgicalwaveform field is used to indicate the waveform of the drivingelectrosurgical signal. In one example, the electrosurgical waveformfield 1312 may be two-bits and a ‘00’ in the electrosurgical waveformfield 1312 may indicate no waveform has been selected, a ‘01’ in theelectrosurgical waveform field 1312 may indicate that a monopolar COAGwaveform is to be activated, a ‘10’ in the electrosurgical waveformfield 1312 may indicate that a monopolar CUT waveform is to beactivated, and a ‘11’ in the electrosurgical waveform field 1312 mayindicate that a bipolar COAG waveform is to be activated. It will beevident to a person of skill in the art that this is an example only andin other examples the electrosurgical waveform may have more or fewerbits based on the number of different waveforms supported by theelectrosurgical generators used to drive the electrosurgicalinstrument(s). Specifically, to support more waveforms theelectrosurgical waveform field 1312 may comprise more bits. Examples ofadditional waveforms that may be supported include, but are not limitedto, a bipolar CUT waveform and a BLEND waveform (described above).

In some cases, the token generated by the control unit 810 may compriseinformation in the electrosurgical waveform field 1312 that indicatesthat no waveform has been selected (e.g. it may be set to ‘00’) and onlyif the control unit 810 receives a modified version of the token inwhich the electrosurgical waveform field 1312 indicates a waveform hasbeen selected (e.g. it is non-zero) will the control unit 810 activatean activation switch unit. It will be evident to a person of skill inthe art that this is an example only and that there may be a differentnumber and/or type of supported waveforms and/or the waveforms may beindicated using a different combination of 1's and 0's.

The generation time information field 1308 comprises informationindicating the time at which the token was generated. As describedabove, in some cases the control unit 810 may be configured to update arolling counter on a periodic basis and the information indicating thetime at which the token was generated may comprise the value of thecounter at the time the token is generated.

The token-based approach described above means that the latency can beverified end to end without reference to more complicated clocksynchronisation or link-specific latency detection methods. It alsocontrols the risk that a computer system between the external computingdevice and the electrosurgical connection unit might get stuck repeatingthe same stale activation state and renders such behaviour harmless.

Reference is now made to FIG. 14 which illustrates an exampletoken-based method 1400 for remotely activating an electrosurgicalinstrument 712 attached to a surgical robot arm 702. The method 1400begins at block 1402 where the control unit 810 associated with thesurgical robot arm, which may be referred to herein as the surgicalrobot arm control unit, generates a token comprising informationindicating a time at which the token was generated. In some cases, thecontrol unit 810 may be configured to periodically (e.g. at a frequencyof 1 kHz) increment, or modify, a rolling counter (e.g. a 16-bitcounter) and the information in a token indicating the time at which thetoken was generated may comprise the value of the counter at the timethe token was generated. In some cases, the token may also compriseinformation uniquely identifying the surgical robot arm.

In some cases, the token may further comprise validation informationthat indicates whether the token is valid. For example, as describedabove, the token may comprise an error detection code, such as, but notlimited to a cycle redundancy check (CRC) code, that is based on some orall of the information (e.g. fields) in the token.

At block 1404, the surgical robot control unit 810 transmits the token,directly or indirectly (e.g. via the communication module 818) to anexternal computing device (e.g. robot control unit 718). The token maybe transmitted to the external computing device using any suitablecommunication means, such as those described above in relation to thecommunication module 818. The method 1400 then proceeds to block 1406.

At block 1406, the token is received at the external computing device(e.g. robot control unit 718). The method 1400 then proceeds to block1408. In some cases, the method 1400 may only proceed to block 1408 ifit is determined that the token relates to a surgical robot arm that iscurrently being controlled by a user; if it is determined (e.g. from thevalidation information) that the token is valid; and/or if it isdetermined that the surgical robot arm to which the token relatescurrently has an electrosurgical instrument attached thereto. If one ormore of these conditions are determined not to be true then the tokenmay be discarded and/or invalidated (e.g. zeroed) and the method 1400may end.

At block 1408, the external computing device determines whether it hasreceived input indicating that the electrosurgical instrument 712 is tobe activated. For example, as described above, the command interface maycomprise a display and one or more devices, such as, but limited to handcontrollers or joysticks, that are used to control the surgical robotarm. The surgeon or other user may be able to indicate that a selectedelectrosurgical instrument (e.g. the electrosurgical instrument attachedto the surgical robot arm currently being controlled by the device) isto be activated by selecting or otherwise activating an input on thedevice, such as, but not limited to an electrosurgical activationbutton. In these cases, when the user activates the input (e.g.electrosurgical activation button) the external computing device (e.g.robot control unit 718) may receive input that the selectedelectrosurgical instrument is to be activated. If the external computingdevice has received input indicating that the electrosurgical instrument712 is to be activated, the method 1400 proceeds to block 1410.Otherwise the method 1400 ends.

At block 1410, in response to receiving input at the external computingdevice (e.g. robot control unit 718) indicating that the electrosurgicalinstrument 712 is to be activated, a modified version of the receivedtoken, which may also be referred to as an updated token, is transmittedto the surgical robot control unit 810. The modified version of thetoken indicates that the electrosurgical instrument 712 is to beactivated.

In some cases, the modified version of the token may be generated byadding information to the token indicating the desired waveform toactivate the electrosurgical instrument. For example, the initial tokengenerated by the surgical robot arm control unit 810 may indicate thatno waveform has been selected (e.g. the electrosurgical waveform field1312 may be ‘00’) and by modifying the token to indicate a particularwaveform the modified version of the token indicates that theelectrosurgical instrument is to be activated As described above, thedesired waveform may be any waveform supported by the system (e.g.capable of being generated by the electrosurgical generators used todrive the electrosurgical instrument(s)). Examples of waveforms that maybe supported by the system include, but are not limited to, monopolarcoagulation (COAG) waveform, monopolar cut (CUT) waveform, bipolarcoagulation (COAG) waveform, bipolar cut (CUT) waveform, and one or moreBLEND waveforms.

In some cases, the surgeon, or other user, may be able to select, via agraphical user interface displayed on the display of the user interfacethe waveform of the driving electrosurgical signal and when the externalcomputing devices receives an indication that the surgical instrument isto be activated then the token is modified to indicate the waveformpre-selected by the user is the desired waveform. Where the modifiedversion of the token comprises information indicting the waveform of thedriving electrosurgical signal, prior to transmitting the modifiedversion of the token, the external computing device (e.g. robot controlunit 710) may determine if the electrosurgical instrument to beactivated supports the waveform indicated in the modified version of thetoken. In these cases, the external computing device may only transmitthe modified version of the token to the surgical robot arm control unitif it is determined that the electrosurgical instrument supports theindicated waveform.

In some cases, where the token has validation information, modifying thetoken to generate the modified version of the token many furthercomprise modifying the validation information (e.g. CRC code) in thetoken to reflect the changes to the token (e.g. waveform informationetc.). In this way the modified version of the token may compriseupdated validation information (e.g. CRC code).

In some cases, prior to transmitting the modified version of the tokento the surgical robot arm control unit, the external computing device(e.g. robot control unit 718) may determine, from the validationinformation in the modified version of the token, whether the modifiedversion of the token is valid. If the modified version of the token isnot valid then it may have been corrupted and it is not safe to send itto the surgical robot arm control unit. Accordingly, in these cases, theexternal computing device may only transmit the modified version of thetoken to the surgical robot arm control unit if it is determined thatthe modified version of the token is valid.

In some cases, prior to transmitting the modified version of the tokento the surgical robot arm control unit, the external computing device(e.g. robot control unit 718) may determine whether the surgical robotarm is currently being controlled by a user. If the surgical robot armis not currently being controlled by a user then it may not be safe toactivate an electrosurgical instrument attached thereto. In these cases,the external computing device may only transmit the modified version ofthe token to the surgical robot arm control unit if it is determinedthat the surgical robot arm to which the surgical instrument is attachedis currently being controlled by a user.

In some cases, the external computing device may receive input that theelectrosurgical instrument is to be activated when a user activates aninput on a device used to control the surgical robot arm. In thesecases, the external computing device may only transmit the modifiedversion of the token to the surgical robot arm control unit if the inputis received when the device is being used by a user. Where the device isa hand controller, joystick or the like the device may comprise a sensorto detect when the device is being grasped or held by a user and theexternal computing device may determine that the device is being used bythe user if the sensor had detected that the device is being grasped orheld by the user.

Once the modified version of the token has been transmitted to thesurgical robot arm control unit, the method 1400 proceeds to block 1412.

At block 1412, the surgical robot arm control unit 810 determineswhether the modified version of the token has been received within athreshold amount of time from when the token was generated. Where, asdescribed above, the control unit 810 periodically updates a counter andthe information in a token that indicates the time at which the tokenwas generated is the value of the counter at the time the token wasgenerated, the surgical robot arm control unit 810 may compare theinformation in the modified version of the token indicating the time atwhich the token was generated to the current value of the counter todetermine whether the modified version of the token was received withinthe threshold amount of time from when the token was generated. Forexample, the control unit 810 may compute the difference between thecounter value in the modified version of the token and the currentcounter value and determine that the token was received within thethreshold amount of time if the difference does not exceed a threshold.

If it is determined that the modified version of the token has beenreceived within the threshold amount of time then the method 1400proceeds to block 1414. Otherwise, the method 1400 ends.

At block 1414, in response to the surgical robot arm control unit 810receiving the modified version of the token within a threshold amount oftime from when the token was generated, one or more signals are outputthat cause the electrosurgical instrument to be activated by a drivingelectrosurgical signal.

In some cases, where a token comprises information uniquely identifyingthe surgical robot arm, the surgical robot arm control unit 810 may onlyoutput the one or more signals if the modified version of the tokencomprises the information that uniquely identifies the surgical robotarm. In other words, in these cases, the surgical robot arm control unit810 may only output the one or more signals if the informationidentifying a surgical robot arm in the modified version of the tokenmatches the identifying information for the surgical robot arm that thecontrol unit 810 controls.

In some cases, where a token comprises validation information, thesurgical robot arm control unit 810 may, prior to outputting the one ormore signals, determine, based on the validation information in themodified version of the token, whether the modified version of the tokenis valid. For example, the surgical robot arm may perform a CRC check onthe CRC code or value in the modified version of the token to determineif the modified version of the token is valid. In these cases, thesurgical robot arm control unit 810 may only output the one or morecontrol signals if it is determined the modified version of the token isvalid.

In some cases, the surgical robot arm control unit 810 may, prior tooutputting of the one or more signals, determine whether theelectrosurgical instrument and/or the surgical robot arm are in asuitable state for electrosurgical activation. The electrosurgicalinstrument and/or the surgical robot arm may be deemed not be in asuitable state for electrosurgical activation if, for example, theelectrosurgical instrument and/or the surgical robot arm are in a faultstate. In these cases, the surgical robot arm may be configured to onlyoutput the one or more signals if it is determined that theelectrosurgical instrument and/or the surgical robot arm are in asuitable state for electrosurgical activation.

Where the modified version of the token comprises information indicatingthe waveform of the driving electrosurgical signal then the surgicalrobot arm control unit 810 may generate the one or more signals so as tocause the electrosurgical instrument to be activated by a drivingelectrosurgical signal with the waveform identified in the modifiedversion of the token.

In some cases, the one or more control signals output by the surgicalrobot arm control unit are provided to an activation switch unit (suchas the activation switch units described above), which causes activationof the activation switch unit. As described above, activation of theactivation switch unit causes an activation signal to be transmitted toan electrosurgical generator. In some cases, the one or more signalsoutput by the surgical robot arm control unit may comprises anoscillating signal, such as, but not limited to a square wave.

In some cases, the modified version of the token may be transmitted fromthe external computing device to the surgical robot arm control unit viaone or more processing units. The one or more processing units may formpart of the external computing device or may be separate and distinctfrom the external computing device. In these cases, any or all of theseprocessing units may be configured to determine whether, at the timethey receive the modified version of the token, that anon-electrosurgical activation state exists; and if anon-electrosurgical activation state is exists, discarding or invalidingthe modified version of the token. As described above, anon-electrosurgical activate state may be any state of the modifiedversion of the token, electrosurgical instrument, or surgical robot armin which the modified version of the token shouldn't be used to activatethe electrosurgical instrument.

Example non-electrosurgical activation states include, but are notlimited to: the modified version of the token is invalid (e.g. asindicated by the validation information); the electrosurgical instrumentdoes not support the waveform indicated in the modified version of thetoken; the surgical robot arm is not currently being controlled by auser; and the surgical robot arm is not in a surgical mode (i.e. a modein which it can be used to perform surgery).

Although the control unit 810 is described as being part of anelectrosurgical connection unit that activates an electrosurgicalinstrument by activating an activation switch unit, it will be evidentto a person of skill in the art that the method may be implemented usingany control unit associated with the surgical robot arm and that theelectrosurgical instrument may be activated using any suitable means.For example, instead of activating an activation switch the one or moresignals may be sent directly or indirectly to an electrosurgicalgenerator which cause the electrosurgical generator to output a drivingelectrosurgical signal which activates the electrosurgical instrument.

The applicant hereby discloses in isolation each individual featuredescribed herein and any combination of two or more such features, tothe extent that such features or combinations are capable of beingcarried out based on the present specification as a whole in the lightof the common general knowledge of a person skilled in the art,irrespective of whether such features or combinations of features solveany problems disclosed herein. In view of the foregoing description itwill be evident to a person skilled in the art that variousmodifications may be made within the scope of the invention.

The invention claimed is:
 1. A method of activating an electrosurgicalinstrument attached to a surgical robot arm, the method comprising:periodically generating, at a surgical robot arm control unit, a tokencomprising information indicating a time at which the token wasgenerated; for each generated token: transmitting the token from thesurgical robot arm control unit to an external computing device;receiving the token at the external computing device; in response to theexternal computing device receiving input indicating that theelectrosurgical instrument is to be activated, transmitting a modifiedversion of the received token to the surgical robot arm control unit,the modified version of the token indicating that the electrosurgicalinstrument is to be activated; and if the surgical robot arm controlunit receives the modified version of the token within a thresholdamount of time from when the token was generated, outputting one or moresignals that cause the electrosurgical instrument to be activated. 2.The method of claim 1, further comprising periodically incrementing arolling counter at the surgical robot arm control unit, and theinformation indicating the time at which the token was generatedcomprises a value of the counter at the time the token was generated. 3.The method of claim 2, wherein the method further comprises comparingthe information in the modified version of the token indicating the timeat which the token was generated to a current value of the counter todetermine whether the modified version of the token was received withinthe threshold amount of time from when the token was generated.
 4. Themethod of claim 1, wherein the token further comprises informationuniquely identifying the surgical robot arm, and the method furthercomprises determining whether the modified version of the tokencomprises the information uniquely identifying the surgical robot arm,and only outputting the one or more signals if it is determined that themodified version of the token comprises the information uniquelyidentifying the surgical robot arm.
 5. The method of claim 2, whereinthe token further comprises validation information indicating whetherthe token is valid, and the method further comprises determining fromthe validation information in the modified version of the token if themodified version of the token is valid, and only outputting the one ormore signals when it is determined that the modified version of thetoken is valid.
 6. The method of claim 5, wherein the validationinformation is an error detection code.
 7. The method of claim 5,wherein the validation information is a cyclic redundancy check code. 8.The method of claim 5, wherein the method further comprises,determining, at the external computing device, whether the modifiedversion of the token is valid from the validation information; and onlytransmitting the modified version of the token to the surgical robot armcontrol unit when it is determined that the modified version of thetoken is valid.
 9. The method of claim 5, wherein the modified versionof the token comprises modified validation information.
 10. The methodof claim 1, wherein the modified version of the token comprisesinformation indicating a waveform of a driving electrosurgical signal toactivate the electrosurgical instrument.
 11. The method of claim 10,wherein the waveform is one of a monopolar coagulation waveform, amonopolar cut waveform, a bipolar coagulation waveform, a bipolar cutwaveform and a blend waveform.
 12. The method of claim 10, wherein theone or more signals output by the surgical robot arm control unit causethe electrosurgical instrument to be activated by a drivingelectrosurgical signal with the waveform indicated in the modifiedversion of the token.
 13. The method of claim 10, wherein the methodfurther comprises determining whether the electrosurgical instrumentsupports the waveform indicated in the modified version of the token,and only transmitting the modified version of the token to the surgicalrobot arm control unit if it is determined that the electrosurgicalinstrument supports the waveform indicated in the modified version ofthe token.
 14. The method of claim 1, wherein the method furthercomprises determining whether the surgical robot arm is currently beingcontrolled by a user, and only transmitting the modified token to thesurgical robot arm control unit if it is determined that the surgicalrobot arm is currently being controlled by a user.
 15. The method ofclaim 1, wherein the modified version of the token is transmitted fromthe external computing device to the surgical robot arm control unit viaone or more processors, and the method further comprises, if any of theone or more processors detects a non-electrosurgical activation statewhen the modified version of the token is received at that processor,discarding or invalidating the modified version of the token.
 16. Themethod of claim 1, wherein the external computing device receives inputindicating that the electrosurgical instrument is to be activated when auser activates an input on a device used to control the surgical robotarm and the modified version of the token is only transmitted to thesurgical robot arm control unit if it is detected that the device iscurrently being used to control the surgical robot arm.
 17. The methodof claim 1, wherein the method further comprises, in response toreceiving the modified version of the token, determining at the surgicalrobot arm control unit whether the electrosurgical instrument and/or thesurgical robot arm are in a suitable state for electrosurgicalactivation, and the one or more signals are only output if it isdetermined that the electrosurgical instrument and/or surgical robot armare in a suitable state for electrosurgical activation.
 18. The methodof claim 1, wherein the one or more signals output by the surgical robotarm control unit are provided to an activation switch unit which causesactivation of the activation switch unit, wherein activation of theactivation switch unit causes an activation signal to be transmitted toan electrosurgical generator.
 19. The method of claim 1, wherein the oneor more signals output by the surgical robot arm control unit comprisesan oscillating signal.
 20. A system to activate an electrosurgicalinstrument attached to a surgical robot arm, the system comprising: anexternal computing device configured to: periodically receive a tokenfrom a surgical robot arm control unit, the token comprising informationindicating a time at which the token was generated by the surgical robotarm control unit; and for each received token, in response to receivinginput indicating that the electrosurgical instrument is to be activated,transmit a modified version of the token to the surgical robot armcontrol unit, the modified version of the token indicating that theelectrosurgical instrument is to be activated; and the surgical robotarm control unit in communication with the external computing device,the surgical robot arm control unit configured to: receive the modifiedversion of the token; and in response to the modified version of thetoken being received within a threshold amount of time from when thetoken was generated, outputting one or more signals that cause theelectrosurgical instrument to be activated.